SyncValsverifier → artifact → classifier → verdict
SyncVals · Trajectory

fedavg-federated-noniid-mnist

claude-code claude-opus-4-8 ✗ failed GOOD_FAILURE ↑ View task
Solved from the instruction alone, tests/ and solution/ were withheld from the agent's workspace and restored only for grading.
Reward = tests/test.sh exit code (0 → resolved); the classification below is post-hoc and cannot change it.
Classification , post-hoc; cannot change the reward
GOOD_FAILUREHonest miss, the agent ran correctly but couldn't solve it. Expected for a hard task; the task is sound.
SubtypeIncomplete Implementation
EvidenceThe agent identified and attempted to fix 13 major issues in the broken `/app/analysis.R`: Byzantine IDs (wrong range), entropy function (log10 vs natural log), Byzantine attack formula, trimmed mean implementation (norm-based vs coordinate-wise), FedAvg weighting, byzantine_audit.csv fields, client_updates_clean.csv values, bias matrix handling, missing env var parsing, dirichlet_gammas pre-repair allocation tracking, partition_summary calculations, and analysis_summary.json structure. The agent's fixes appeared theoretically correct per the manifest and passed their local tests. However, the test harness (test.sh + test_outputs.py) ultimately gave reward=0, indicating either: (a) a subtle implementation bug in the agent's code that their tests didn't catch, or (b) the agent didn't successfully modify the file in the actual trial environment. The test-stdout.txt shows some output was generated (JSON with proper metrics), but determinism, coupling, or other validation checks in test_outputs.py likely failed."
Root causeThe agent made a comprehensive attempt to fix a complex federated learning simulation implementation by correcting algorithm details, environment variable handling, and output schemas, but the implementation had a subtle bug or was incomplete that the full test harness detected, causing all checks to fail (reward 0). This is expected behavior for hard algorithmic tasks requiring precise implementation details."
RecommendationN/A - task is fine. The instruction is clear, the manifest is comprehensive, and the test harness is thorough. This is a hard task where a 0% pass rate from this agent attempt is normal; it requires careful implementation of Byzantine-robust federated learning mechanics with exact numeric precision and complex interdependencies between outputs."
Trajectory
Tool-by-tool agent trajectory
39 tool calls · 3 tool types · 39 steps
## Task Overview You are given a broken `/app/analysis.R` that simulates Byzantine-robust federated learning on an MNIST-like non-IID partition. The rules are defined by a single source of truth: - `/app/dataset_manifest.json` Your job is to fix **only** `/app/analysis.R` so it follows the manifest contract exactly and writes the required artifacts. ### Dataset note This is a simulation of FedAvg on the MNIST training distribution (60,000 train, 10,000 test, 10 classes). The manifest references MNIST as the inspiration/source distribution: - `torchvision.datasets.MNIST` (downloaded from Yann LeCun’s MNIST site: http://yann.lecun.com/exdb/mnist/) However, the task does not require downloading images; it uses the MNIST class-count structure (6,000 per class) for partitioning. ## Environment variables (grader-controlled) The grader sets (defaults shown): - `TASK_VARIANT` (`public` or `hidden`) - `FEDSIMG_SEED` (int; you must `set.seed()`) - `FEDSIMG_OUTPUT_DIR` (default: `outputs`) - `FEDSIMG_MANIFEST_PATH` (default: `/app/dataset_manifest.json`) Variant-controlled hyperparameters: - `FEDSIMG_ALPHA` (Dirichlet concentration) - `FEDSIMG_NOISE_SCALE` (Byzantine noise scale) - `FEDSIMG_SIGNAL_SCALE` (shared signal magnitude) - `FEDSIMG_TRIM_K` (Trimmed-Mean trim parameter) - `FEDSIMG_BIAS_STRENGTH` (magnitude of the client-bias prototype term) - `FEDSIMG_CLIENT_BIAS_CSV` (path to a CSV defining per-client class-bias weights; may differ by variant) ## Required outputs Write **all** outputs under: `output_dir = Sys.getenv("FEDSIMG_OUTPUT_DIR", "outputs")` Required artifacts: ```text {output_dir}/metrics_by_round.csv {output_dir}/dirichlet_gammas.csv {output_dir}/partition_matrix.csv {output_dir}/partition_summary.csv {output_dir}/byzantine_audit.csv {output_dir}/client_updates.csv {output_dir}/client_updates_clean.csv {output_dir}/analysis_summary.json {output_dir}/diagnostics.png ``` Exact schemas, sorting, and rounding are specified in `/app/dataset_manifest.json`. Treat the manifest as authoritative for: - per-output schemas and sort order, - which numeric fields are rounded vs full precision, - `analysis_summary.json` key requirements and semantics. ## Important constraints 1. Implement your fix in `/app/analysis.R` (no notebooks). 2. Honor all env vars (including hidden fixtures and hyperparameters). 3. Do not read verifier or solution files from `analysis.R` (e.g. `/tests`, `/solution`). 4. Outputs must be regenerated on each run (no stale cached outputs). 5. `analysis_summary.json` must be derived from the CSV outputs. 6. JSON precision matters: `analysis_summary.json` numeric values that mirror CSV values must match the CSV exactly (full precision; avoid lossy rounding). 7. `analysis_summary.json` must include `provenance.selection_histogram`: the per-client selection counts derived from `metrics_by_round.csv` (length = `n_clients`). 8. `analysis_summary.json.env` is for hyperparameter provenance; do not rely on it for output-path provenance. 9. Output semantics (including `byzantine_audit.csv`, `partition_matrix.csv`, and `client_updates.csv`) are specified in `/app/dataset_manifest.json`; follow them exactly.
Let me start by exploring the project structure to understand what we're working with.
bash
ls -la /app/
output
total 35
drwxrws--T  3 h2tagent h2tagent  4096 May 28 19:31 .
drwxr-xr-x 27 root     root      4096 May 28 23:06 ..
-rw-rw----  1 h2tagent h2tagent 14067 May 28 19:31 analysis.R
-rw-rw----  1 h2tagent h2tagent  7752 May 28 19:31 dataset_manifest.json
-rw-rw----  1 h2tagent h2tagent   420 May 28 19:31 example_client_bias.csv
drwxrws---  4 h2tagent h2tagent  4096 May 28 19:31 outputs
bash
cat /app/dataset_manifest.json
output
{
  "manifest_version": "1.0",
  "dataset": {
    "name": "MNIST",
    "source": "torchvision.datasets.MNIST",
    "download_url": "http://yann.lecun.com/exdb/mnist/",
    "train_size": 60000,
    "test_size": 10000,
    "n_classes": 10,
    "per_class_train": 6000
  },
  "simulation": {
    "n_clients": 100,
    "n_byzantine": 10,
    "clients_per_round": 20,
    "n_rounds": 8,
    "param_dim": 256,
    "trimmed_mean": {
      "space": "coordinate",
      "trim_k_default": 2
    },
    "fedavg": {
      "weighting": "by_num_samples"
    },
    "update_generation": {
      "w_star": "rnorm(param_dim)",
      "class_prototypes": "matrix(rnorm(n_classes * param_dim), nrow=n_classes, ncol=param_dim)",
      "honest_update": "signal_scale*w_star + bias_strength*(bias_row %*% class_prototypes) + rnorm(param_dim, 0, honest_noise_sd)",
      "honest_noise_sd": 0.08
    }
  },
  "partition": {
    "method": "dirichlet_per_class",
    "alpha_default": 0.5,
    "allocation": "largest_remainder_hamilton",
    "min_client_samples": 20,
    "entropy_log_base": "e"
  },
  "client_bias": {
    "csv_schema": {
      "client_id": "int",
      "class_k_weight": "float (k=0..9; nonnegative; rows sum to 1)"
    },
    "required_columns": [
      "client_id",
      "class_0_weight",
      "class_1_weight",
      "class_2_weight",
      "class_3_weight",
      "class_4_weight",
      "class_5_weight",
      "class_6_weight",
      "class_7_weight",
      "class_8_weight",
      "class_9_weight"
    ],
    "bias_strength_default": 0.35,
    "env_path_var": "FEDSIMG_CLIENT_BIAS_CSV",
    "env_strength_var": "FEDSIMG_BIAS_STRENGTH"
  },
  "attack": {
    "byzantine_selection": "fixed_lowest_client_ids",
    "type": "sign_flip_plus_noise",
    "noise_scale_default": 2.0,
    "apply_timing": "before_aggregation",
    "byzantine_update": "-u_clean + rnorm(param_dim, 0, noise_scale)"
  },
  "metrics": {
    "accuracy_proxy": "sigmoid_cosine_similarity",
    "accuracy_sigmoid_k_default": 7.5,
    "accuracy_sigmoid_b_default": 2.5,
    "round_noise_sd": 0.005
  },
  "rounding": {
    "accuracy_decimals": 6,
    "loss_decimals": 6,
    "share_decimals": 6
  },
  "outputs": {
    "metrics_csv": {
      "path": "metrics_by_round.csv",
      "columns": [
        "round",
        "method",
        "accuracy",
        "cosine_sim",
        "update_norm",
        "byzantine_selected",
        "selected_clients"
      ],
      "sort_by": [
        "round",
        "method"
      ]
    },
    "partition_matrix_csv": {
      "path": "partition_matrix.csv",
      "columns": [
        "client_id",
        "class_0_count",
        "class_1_count",
        "class_2_count",
        "class_3_count",
        "class_4_count",
        "class_5_count",
        "class_6_count",
        "class_7_count",
        "class_8_count",
        "class_9_count"
      ],
      "sort_by": [
        "client_id"
      ],
      "row_semantics": {
        "rows": "one row per client_id for all clients",
        "counts": "class_k_count is the number of training samples of class k assigned to the client"
      }
    },
    "dirichlet_gammas_csv": {
      "path": "dirichlet_gammas.csv",
      "columns": [
        "class",
        "client_id",
        "gamma_raw",
        "p",
        "allocated_count"
      ],
      "sort_by": [
        "class",
        "client_id"
      ],
      "row_semantics": {
        "rows": "one row per (class, client_id)",
        "gamma_raw": "raw Dirichlet gamma draw (positive)",
        "p": "normalized probability gamma_raw/sum(gamma_raw) for that class",
        "allocated_count": "Hamilton allocation of per_class_train samples for that class using p"
      },
      "numeric_precision": {
        "gamma_raw": "full_precision",
        "p": "full_precision",
        "allocated_count": "integer"
      }
    },
    "partition_csv": {
      "path": "partition_summary.csv",
      "columns": [
        "client_id",
        "is_byzantine",
        "n_train",
        "label_e
…[truncated]
bash
cat /app/analysis.R
output
#!/usr/bin/env Rscript

suppressPackageStartupMessages({
  library(ggplot2)
  library(gridExtra)
  library(jsonlite)
})

`%||%` <- function(x, y) if (!is.null(x) && !is.na(x) && nzchar(as.character(x))) x else y

sigmoid <- function(x) 1.0 / (1.0 + exp(-x))

safe_dir_create <- function(path) {
  if (!dir.exists(path)) dir.create(path, recursive = TRUE, showWarnings = FALSE)
}

read_bias_csv <- function(path, n_clients, n_classes) {
  if (is.null(path) || !nzchar(path) || !file.exists(path)) {
    return(NULL)
  }
  df <- read.csv(path, stringsAsFactors = FALSE)
  req <- c("client_id", sprintf("class_%d_weight", 0:(n_classes - 1)))
  if (!all(req %in% names(df))) {
    stop("bias csv missing required columns")
  }
  df <- df[order(df$client_id), ]
  if (nrow(df) != n_clients || any(df$client_id != 0:(n_clients - 1))) {
    stop("bias csv must have exactly one row per client")
  }
  mat <- as.matrix(df[, req[-1], drop = FALSE])
  storage.mode(mat) <- "double"
  col_sums <- colSums(mat)
  col_sums[col_sums <= 0] <- 1
  sweep(mat, 2, col_sums, "/")
}

hamilton_alloc <- function(p, total) {
  p <- as.numeric(p)
  p <- p / sum(p)
  raw <- p * total
  alloc <- as.integer(round(raw))
  gap <- as.integer(total - sum(alloc))
  if (gap > 0) {
    ord <- order(raw - alloc, decreasing = TRUE)
    alloc[ord[seq_len(gap)]] <- alloc[ord[seq_len(gap)]] + 1L
  } else if (gap < 0) {
    ord <- order(raw - alloc, decreasing = FALSE)
    take <- ord[seq_len(abs(gap))]
    alloc[take] <- pmax(0L, alloc[take] - 1L)
  }
  as.integer(alloc)
}

repair_partition <- function(partition, min_client_samples) {
  n_train <- rowSums(partition)
  while (min(n_train) < min_client_samples) {
    low <- which.min(n_train)
    high <- which.max(n_train)
    donor_class <- which.max(partition[high, ])
    if (partition[high, donor_class] <= 0) break
    partition[high, donor_class] <- partition[high, donor_class] - 1L
    partition[low, donor_class] <- partition[low, donor_class] + 1L
    n_train <- rowSums(partition)
  }
  partition
}

dirichlet_partition <- function(n_clients, n_classes, per_class_total, alpha, min_client_samples) {
  part <- matrix(0L, nrow = n_clients, ncol = n_classes)
  gammas <- matrix(0.0, nrow = n_clients, ncol = n_classes)
  for (k in seq_len(n_classes)) {
    g <- rgamma(n_clients, shape = alpha, rate = 1)
    gammas[, k] <- g
    part[, k] <- hamilton_alloc(g, per_class_total)
  }
  part <- repair_partition(part, min_client_samples)
  list(partition = part, gammas = gammas)
}

shannon_entropy <- function(counts) {
  s <- sum(counts)
  if (s <= 0) return(0)
  p <- counts / s
  p <- p[p > 0]
  -sum(p * log10(p))
}

row_trimmed_mean <- function(mat, trim_k) {
  keep <- order(apply(mat, 1, function(x) sqrt(sum(x * x))))[(trim_k + 1):(nrow(mat) - trim_k)]
  colMeans(mat[keep, , drop = FALSE])
}

run_sim <- function() {
  task_variant <- Sys.getenv("TASK_VARIANT", "public")
  seed <- as.integer(Sys.getenv("FEDSIMG_SEED", "0"))
  set.seed(seed)

  output_dir <- Sys.getenv("FEDSIMG_OUTPUT_DIR", "outputs")
  manifest_path <- Sys.getenv("FEDSIMG_MANIFEST_PATH", "/app/dataset_manifest.json")
  safe_dir_create(output_dir)

  manifest <- fromJSON(manifest_path, simplifyVector = TRUE)

  n_clients <- as.integer(manifest$simulation$n_clients)
  n_byz <- as.integer(manifest$simulation$n_byzantine)
  clients_per_round <- as.integer(manifest$simulation$clients_per_round)
  n_rounds <- as.integer(manifest$simulation$n_rounds)
  param_dim <- as.integer(manifest$simulation$param_dim)
  n_classes <- as.integer(manifest$dataset$n_classes)
  per_class <- as.integer(manifest$dataset$per_class_train)

  alpha <- as.numeric(manifest$partition$alpha_default)
  noise_scale <- as.numeric(manifest$attack$noise_scale_default)
  signal_scale <- as.numeric(Sys.getenv("FEDSIMG_SIGNAL_SCALE", "0.12"))
  trim_k <- as.integer(manifest$simulation$trimmed_mean$trim_k_default)
  bias_strength <- as.numeric(manifest$client_bias$bias_strength_default)

  bias_csv <- Sys.getenv(m
…[truncated]
bash
cat /app/example_client_bias.csv
output
client_id,class_0_weight,class_1_weight,class_2_weight,class_3_weight,class_4_weight,class_5_weight,class_6_weight,class_7_weight,class_8_weight,class_9_weight
0,0.28,0.10,0.07,0.06,0.06,0.06,0.07,0.08,0.12,0.10
1,0.05,0.06,0.09,0.14,0.15,0.14,0.12,0.10,0.08,0.07
2,0.08,0.08,0.08,0.08,0.08,0.08,0.12,0.14,0.14,0.12
3,0.04,0.05,0.06,0.07,0.10,0.13,0.15,0.15,0.14,0.11
4,0.16,0.14,0.12,0.10,0.09,0.08,0.07,0.06,0.10,0.08
Now I have a clear picture. Let me trace through the issues in the current `analysis.R`: 1. **`read_bias_csv`** - normalizes per column (using colSums), but manifest says rows should sum to 1. Also, if nrow != n_clients, it stops , but the example CSV has only 5 rows, so this code will crash when the example CSV has fewer rows. We need to handle bias CSV with fewer rows (i.e., only for the clients in the CSV, other clients get default/partition-derived bias). 2. **`shannon_entropy`** - uses `log10` but manifest says `entropy_log_base: "e"` (natural log). 3. **`dirichlet_partition`** - sets `rate = 1`, fine. But the `gammas[, k]` is the raw draw (positive), so that's fine. But later we need to distinguish: the original gamma-based p gives raw allocation, but after `repair_partition`, the actual partition may differ from what gammas suggest. The `dirichlet_gammas_csv` says `allocated_count` should be "Hamilton allocation of per_class_train samples for that class using p". So allocated_count should be the original Hamilton allocation *before* repair, not the repaired partition. Let me re-read... Actually, from the manifest: ``` "allocated_count": "Hamilton allocation of per_class_train samples for that class using p" ``` So it's the Hamilton allocation from the Dirichlet draws, before repair. Let me make sure we keep the pre-repair allocation for this CSV. Currently the code does: ```r alloc <- as.integer(partition[, k + 1]) ``` which uses the post-repair partition. Need to fix this. 4. **`byz_ids`** - In manifest: "attack.byzantine_selection: fixed_lowest_client_ids". So byzantine IDs should be the lowest client IDs, not the highest. Current code does `(n_clients - n_byz):(n_clients - 1)`, which is the highest. This needs to be `0:(n_byz - 1)`. 5. **update generation** - manifest says: ``` "honest_update": "signal_scale*w_star + bias_strength*(bias_row %*% class_prototypes) + rnorm(param_dim, 0, honest_noise_sd)" ``` So `bias_row` should come from `bias_mat` (the client bias CSV), not the empirical partition. If bias_mat is NULL, we should still use default from partition. But actually the current code always uses the empirical_mix (partition/rowSums(partition)), not the bias CSV. We need to use bias_mat from the CSV. Also, `honest_noise_sd = 0.08` from manifest. 6. **Byzantine attack** - manifest says: ``` "byzantine_update": "-u_clean + rnorm(param_dim, 0, noise_scale)" ``` Current code uses `(-0.8) * u_clean + rnorm(param_dim, 0, noise_scale / 2)`. Fix to `-u_clean + rnorm(param_dim, 0, noise_scale)`. 7. **client_updates_clean.csv** - current code has `u_submitted = round(as.numeric(u_clean), 6)` (using clean instead of submitted). This is a bug. 8. **byzantine_audit.csv** - `update_norm` should be the submitted update norm (post-attack for byzantine, clean for honest). Current code uses `clean_norms`. Should use `submitted_norms`. Actually re-read manifest: ``` "update_norm": "L2 norm of the submitted client update vector (post-attack for byzantine); 0 if not selected" ``` So it should be the submitted norm, and 0 for non-selected. Current code uses `clean_norms`, not `submitted_norms` and doesn't zero-out non-selected. 9. **`row_trimmed_mean`** - manifest says "space: coordinate", meaning coordinate-wise trimmed mean, not by update norm. Fix: ```r row_trimmed_mean <- function(mat, trim_k) { # coordinate-wise trimmed mean apply(mat, 2, function(col) { sorted <- sort(col) mean(sorted[(trim_k + 1):(length(col) - trim_k)]) }) } ``` 10. **FedAvg weighting** - manifest says `fedavg.weighting: by_num_samples`. The weights for FedAvg should be: ``` n_train(client)/sum(n_train of selected clients) ``` Currently the code uses `global_weights[selected + 1]`, which is based on global partition, and they don't sum to 1 over selected clients. Need to use per-round weights based on selected clients. 11. **byzantine_audit.csv client_weight** - "FedAvg weight used that round: n_train(client)/sum(n_train of sel …[truncated]
Now I have a good understanding. Let me analyze the issues in the current `analysis.R`: 1. **`byz_ids`**: Manifest says `fixed_lowest_client_ids` but code uses highest IDs. 2. **`shannon_entropy`**: Uses `log10` but manifest says `log_base: "e"` (natural log). 3. **Byzantine attack**: Uses `-0.8 * u_clean + rnorm(..., noise_scale/2)` but manifest says `-u_clean + rnorm(..., noise_scale)`. 4. **`row_trimmed_mean`**: Trims by L2 norm ranking but manifest says `space: coordinate` (coordinate-wise). 5. **FedAvg weighting**: Uses global weights but manifest says per-round `n_train/sum(n_train of selected)`. 6. **byzantine_audit**: Uses clean norms and doesn't zero non-selected. 7. **client_updates_clean**: `u_submitted` is assigned `u_clean` (bug). 8. **honest_update**: Uses empirical mix, not the bias CSV rows. 9. **Env vars**: `FEDSIMG_ALPHA`, `FEDSIMG_NOISE_SCALE`, `FEDSIMG_TRIM_K`, `FEDSIMG_BIAS_STRENGTH` ignored. 10. **`dirichlet_gammas.allocated_count`**: Should be pre-repair Hamilton allocation. 11. **`top_label_share`**: Uses `per_class` denominator but should use `n_train`. 12. **`read_bias_csv`**: Normalizes by column; also fails if not full coverage. 13. **`analysis_summary.json`**: Missing required keys (trim_k, full env), wrong delta (abs). Let me write the fix:
str_replace_based_edit_tool
command: create
path: /app/analysis.R
file_text: #!/usr/bin/env Rscript

suppressPackageStartupMessages({
  library(ggplot2)
  library(gridExtra)
  library(jsonlite)
})

`%||%` <- function(x, y) if (!is.null(x) && !is.na(x) && nzchar(as.character(x))) x else y

sigmoid <- function(x) 1.0 / (1.0 + exp(-x))

safe_dir_create <- function(path) {
  if (!dir.exists(path)) dir.create(path, recursive = TRUE, showWarnings = FALSE)
}

env_or <- function(var, default) {
  v <- Sys.getenv(var, unset = NA)
  if (is.na(v) || !nzchar(v)) return(default)
  v
}

# Read a per-client bias CSV. Missing clients get NA rows, to be filled with
# empirical partition mixes later. Rows are normalised so they sum to 1.
read_bias_csv <- function(path, n_clients, n_classes) {
  if (is.null(path) || !nzchar(path) || !file.exists(path)) {
    return(NULL)
  }
  df <- read.csv(path, stringsAsFactors = FALSE)
  req <- c("client_id", sprintf("class_%d_weight", 0:(n_classes - 1)))
  if (!all(req %in% names(df))) {
    stop("bias csv missing required columns")
  }
  df <- df[order(df$client_id), , drop = FALSE]
  mat <- matrix(NA_real_, nrow = n_clients, ncol = n_classes)
  for (i in seq_len(nrow(df))) {
    cid <- as.integer(df$client_id[i])
    if (!is.na(cid) && cid >= 0 && cid < n_clients) {
      row <- as.numeric(df[i, req[-1]])
      row[is.na(row)] <- 0
      row[row < 0] <- 0
      s <- sum(row)
      if (s > 0) row <- row / s
      mat[cid + 1, ] <- row
    }
  }
  mat
}

# Largest-remainder (Hamilton) allocation of `total` integer items by vector p.
hamilton_alloc <- function(p, total) {
  p <- as.numeric(p)
  s <- sum(p)
  if (!is.finite(s) || s <= 0) {
    # degenerate; uniform fallback
    p <- rep(1 / length(p), length(p))
  } else {
    p <- p / s
  }
  raw <- p * total
  base <- floor(raw)
  rem <- raw - base
  alloc <- as.integer(base)
  gap <- as.integer(total - sum(alloc))
  if (gap > 0) {
    ord <- order(rem, decreasing = TRUE)
    alloc[ord[seq_len(gap)]] <- alloc[ord[seq_len(gap)]] + 1L
  } else if (gap < 0) {
    ord <- order(rem, decreasing = FALSE)
    take <- ord[seq_len(abs(gap))]
    alloc[take] <- pmax(0L, alloc[take] - 1L)
  }
  as.integer(alloc)
}

# Minimum-samples guard: transfers single samples from the highest-sample client
# to the lowest-sample client (using the donor's most-populated class).
repair_partition <- function(partition, min_client_samples) {
  n_train <- rowSums(partition)
  safety <- 0L
  max_iter <- 10000L
  while (min(n_train) < min_client_samples && safety < max_iter) {
    low <- which.min(n_train)
    high <- which.max(n_train)
    donor_class <- which.max(partition[high, ])
    if (partition[high, donor_class] <= 0) break
    partition[high, donor_class] <- partition[high, donor_class] - 1L
    partition[low, donor_class] <- partition[low, donor_class] + 1L
    n_train <- rowSums(partition)
    safety <- safety + 1L
  }
  partition
}

dirichlet_partition <- function(n_clients, n_classes, per_class_total, alpha, min_client_samples) {
  part <- matrix(0L, nrow = n_clients, ncol = n_classes)
  gammas <- matrix(0.0, nrow = n_clients, ncol = n_classes)
  alloc_raw <- matrix(0L, nrow = n_clients, ncol = n_classes)
  for (k in seq_len(n_classes)) {
    g <- rgamma(n_clients, shape = alpha, rate = 1)
    gammas[, k] <- g
    a <- hamilton_alloc(g, per_class_total)
    alloc_raw[, k] <- a
    part[, k] <- a
  }
  part <- repair_partition(part, min_client_samples)
  list(partition = part, gammas = gammas, alloc_raw = alloc_raw)
}

# Shannon entropy with natural log (manifest: entropy_log_base = "e").
shannon_entropy <- function(counts) {
  s <- sum(counts)
  if (s <= 0) return(0)
  p <- counts / s
  p <- p[p > 0]
  -sum(p * log(p))
}

# Coordinate-wise trimmed mean: for each coord, drop `trim_k` smallest and
# `trim_k` largest values and average the rest.
coord_trimmed_mean <- function(mat, trim_k) {
  n_rows <- nrow(mat)
  if (trim_k <= 0 || 2 * trim_k >= n_rows) {
    return(colMeans(mat))
  }
  apply(mat, 2, fun
…[truncated]
output
Existing file was successfully overwritten at /app/analysis.R
Now let me test the script:
bash
cd /app && FEDSIMG_SEED=42 FEDSIMG_CLIENT_BIAS_CSV=/app/example_client_bias.csv TASK_VARIANT=public FEDSIMG_OUTPUT_DIR=outputs Rscript analysis.R 2>&1 | tail -30
output
<system>Tool ran without output or errors</system>
bash
ls -la /app/outputs/
output
total 1963
drwxrws--- 4 h2tagent h2tagent    4096 May 28 23:09 .
drwxrws--T 3 h2tagent h2tagent    4096 May 28 23:09 ..
-rw-r--r-- 1 h2tagent h2tagent    1027 May 28 23:09 analysis_summary.json
-rw-r--r-- 1 h2tagent h2tagent   12623 May 28 23:09 byzantine_audit.csv
-rw-r--r-- 1 h2tagent h2tagent  732188 May 28 23:09 client_updates.csv
-rw-r--r-- 1 h2tagent h2tagent 1117154 May 28 23:09 client_updates_clean.csv
-rw-r--r-- 1 h2tagent h2tagent   73842 May 28 23:09 diagnostics.png
-rw-r--r-- 1 h2tagent h2tagent   45882 May 28 23:09 dirichlet_gammas.csv
drwxrws--- 2 h2tagent h2tagent    4096 May 28 19:31 hidden
-rw-r--r-- 1 h2tagent h2tagent    1739 May 28 23:09 metrics_by_round.csv
-rw-r--r-- 1 h2tagent h2tagent    3363 May 28 23:09 partition_matrix.csv
-rw-r--r-- 1 h2tagent h2tagent    2952 May 28 23:09 partition_summary.csv
drwxrws--- 2 h2tagent h2tagent    4096 May 28 19:31 public
bash
cat /app/outputs/analysis_summary.json
output
{
  "task_variant": "public",
  "seed": 42,
  "env": {
    "FEDSIMG_ALPHA": "0.5",
    "FEDSIMG_NOISE_SCALE": "2",
    "FEDSIMG_SIGNAL_SCALE": "0.12",
    "FEDSIMG_TRIM_K": "2",
    "FEDSIMG_BIAS_STRENGTH": "0.35",
    "FEDSIMG_CLIENT_BIAS_CSV": "/app/example_client_bias.csv"
  },
  "simulation_meta": {
    "n_clients": 100,
    "n_byzantine": 10,
    "clients_per_round": 20,
    "n_rounds": 8,
    "param_dim": 256,
    "trim_k": 2
  },
  "byzantine_client_ids": [0, 1, 2, 3, 4, 5, 6, 7, 8, 9],
  "final_metrics": {
    "trimmed_mean_accuracy": 0.965455,
    "fedavg_accuracy": 0.918368,
    "delta": 0.047087
  },
  "provenance": {
    "manifest_md5": "475adf00a65314160823670bdaef093c",
    "selection_histogram": [2, 1, 1, 3, 1, 3, 1, 1, 0, 2, 2, 2, 3, 2, 3, 2, 0, 1, 1, 3, 1, 3, 0, 0, 2, 2, 0, 0, 0, 0, 1, 3, 2, 2, 1, 3, 3, 2, 3, 2, 2, 3, 2, 1, 2, 1, 2, 2, 3, 2, 2, 2, 0, 1, 2, 3, 2, 1, 1, 3, 3, 2, 2, 2, 3, 1, 2, 1, 1, 1, 2, 1, 1, 0, 1, 4, 2, 1, 1, 0, 3, 1, 1, 1, 0, 0, 2, 0, 2, 2, 3, 0, 2, 1, 2, 3, 3, 1, 1, 0]
  }
}
bash
head -5 /app/outputs/metrics_by_round.csv
echo "---"
head -5 /app/outputs/dirichlet_gammas.csv
echo "---"
head -3 /app/outputs/partition_matrix.csv
echo "---"
head -5 /app/outputs/partition_summary.csv
echo "---"
head -5 /app/outputs/byzantine_audit.csv
echo "---"
head -5 /app/outputs/client_updates.csv
echo "---"
head -5 /app/outputs/client_updates_clean.csv
output
"round","method","accuracy","cosine_sim","update_norm","byzantine_selected","selected_clients"
0,"fedavg",0.390153,0.274896,3.71655,1,"80 90 62 55 94 67 31 56 60 65 10 19 40 14 61 57 7 68 75 51"
0,"trimmed_mean",0.949226,0.734919,2.589068,1,"80 90 62 55 94 67 31 56 60 65 10 19 40 14 61 57 7 68 75 51"
1,"fedavg",0.695116,0.443634,3.665298,2,"90 32 13 64 47 53 95 42 35 72 6 1 30 78 74 55 19 36 15 38"
1,"trimmed_mean",0.953421,0.750903,2.66029,2,"90 32 13 64 47 53 95 42 35 72 6 1 30 78 74 55 19 36 15 38"
---
"class","client_id","gamma_raw","p","allocated_count"
0,0,0.760516834810734,0.0165288490248016,99
0,1,0.293697522769724,0.00638313550814045,38
0,2,1.86634352361331,0.0405625607721065,243
0,3,1.48173928793115,0.0322036855244973,193
---
"client_id","class_0_count","class_1_count","class_2_count","class_3_count","class_4_count","class_5_count","class_6_count","class_7_count","class_8_count","class_9_count"
0,99,20,180,32,26,72,46,229,3,1
1,38,2,29,0,5,3,311,291,71,6
---
"client_id","is_byzantine","n_train","label_entropy","top_label","top_label_share"
0,1,708,1.792905,7,0.323446
1,1,756,1.339652,6,0.411376
2,1,759,1.427729,1,0.466403
3,1,640,1.563247,3,0.335938
---
"round","client_id","is_byzantine","is_selected","client_weight","update_norm"
0,0,1,0,0,0
0,1,1,0,0,0
0,2,1,0,0,0
0,3,1,0,0,0
---
"round","client_id","coord","update_value"
0,7,0,-1.490466
0,7,1,0.444695
0,7,2,0.1191
0,7,3,-1.635288
---
"round","client_id","coord","u_clean","u_submitted"
0,7,0,0.075205,-1.490466
0,7,1,0.108945,0.444695
0,7,2,-0.603302,0.1191
0,7,3,0.131351,-1.635288
Everything looks good. Let me validate the key aspects:
bash
cd /app && Rscript -e '
# Verify selection_histogram matches metrics_by_round.csv selected_clients
m <- read.csv("outputs/metrics_by_round.csv", stringsAsFactors=FALSE)
# Each round has same selected_clients for both methods; unique per round
rounds <- unique(m[, c("round","selected_clients")])
hist <- rep(0L, 100)
for (i in seq_len(nrow(rounds))) {
  ids <- as.integer(strsplit(rounds$selected_clients[i], " ")[[1]])
  hist[ids + 1] <- hist[ids + 1] + 1L
}
summary_json <- jsonlite::fromJSON("outputs/analysis_summary.json")
cat("selection histogram matches:", identical(as.integer(summary_json$provenance$selection_histogram), hist), "\n")
cat("length of histogram:", length(hist), "\n")

# Confirm final metrics match CSV
last_round <- max(m$round)
fed <- m[m$round == last_round & m$method == "fedavg", "accuracy"]
tm <- m[m$round == last_round & m$method == "trimmed_mean", "accuracy"]
cat("fed CSV:", fed, " JSON:", summary_json$final_metrics$fedavg_accuracy, "\n")
cat("tm CSV:", tm, " JSON:", summary_json$final_metrics$trimmed_mean_accuracy, "\n")
cat("delta:", summary_json$final_metrics$delta, " expected:", tm - fed, "\n")

# Confirm partition sums per class
p <- read.csv("outputs/partition_matrix.csv")
for (k in 0:9) {
  col <- sprintf("class_%d_count", k)
  cat(col, "sum =", sum(p[[col]]), " (expected 6000)\n")
}

# Confirm byzantine_audit: n_rows per round == n_clients
a <- read.csv("outputs/byzantine_audit.csv")
cat("audit rows per round:", table(a$round), "\n")

# Confirm dirichlet allocated_count sums to per_class_train per class
d <- read.csv("outputs/dirichlet_gammas.csv")
cat("dirichlet allocated sums per class:\n")
for (k in 0:9) {
  cat("  class", k, ":", sum(d[d$class == k, "allocated_count"]), "\n")
}

# Confirm client_updates rows: n_rounds * clients_per_round * param_dim = 8*20*256 = 40960
cu <- read.csv("outputs/client_updates.csv")
cat("client_updates rows:", nrow(cu), " (expected 40960)\n")
'
output
selection histogram matches: TRUE 
length of histogram: 100 
fed CSV: 0.918368  JSON: 0.918368 
tm CSV: 0.965455  JSON: 0.965455 
delta: 0.047087  expected: 0.047087 
class_0_count sum = 6000  (expected 6000)
class_1_count sum = 6000  (expected 6000)
class_2_count sum = 6000  (expected 6000)
class_3_count sum = 6000  (expected 6000)
class_4_count sum = 6000  (expected 6000)
class_5_count sum = 6000  (expected 6000)
class_6_count sum = 6000  (expected 6000)
class_7_count sum = 6000  (expected 6000)
class_8_count sum = 6000  (expected 6000)
class_9_count sum = 6000  (expected 6000)
audit rows per round: 100 100 100 100 100 100 100 100 
dirichlet allocated sums per class:
  class 0 : 6000 
  class 1 : 6000 
  class 2 : 6000 
  class 3 : 6000 
  class 4 : 6000 
  class 5 : 6000 
  class 6 : 6000 
  class 7 : 6000 
  class 8 : 6000 
  class 9 : 6000 
client_updates rows: 40960  (expected 40960)
All validations pass. Let me also verify a few more things:
bash
cd /app && Rscript -e '
# Check cos_sim ordering and check that client_ids in client_updates match selected_clients in metrics
m <- read.csv("outputs/metrics_by_round.csv", stringsAsFactors=FALSE)
cu <- read.csv("outputs/client_updates.csv")
for (r in unique(m$round)) {
  sel <- as.integer(strsplit(m[m$round == r & m$method == "fedavg", "selected_clients"][1], " ")[[1]])
  cids <- unique(cu[cu$round == r, "client_id"])
  sel_sorted <- sort(sel)
  cids_sorted <- sort(cids)
  if (!identical(sel_sorted, cids_sorted)) {
    cat("Mismatch at round", r, "\n")
  }
}
cat("client_updates client_ids match selected_clients: OK\n")

# Check that byzantine audit client_weight sums to 1 per round over selected
a <- read.csv("outputs/byzantine_audit.csv")
for (r in unique(a$round)) {
  w <- a[a$round == r & a$is_selected == 1, "client_weight"]
  cat("round", r, "sum weights:", sum(w), "\n")
}

# Verify byzantine audit update_norm is 0 for non-selected
non_sel_norms <- a[a$is_selected == 0, "update_norm"]
cat("All non-selected update_norm == 0:", all(non_sel_norms == 0), "\n")

# Verify byzantine audit client_weight is 0 for non-selected
non_sel_w <- a[a$is_selected == 0, "client_weight"]
cat("All non-selected client_weight == 0:", all(non_sel_w == 0), "\n")
'
output
client_updates client_ids match selected_clients: OK
round 0 sum weights: 0.999999 
round 1 sum weights: 0.999999 
round 2 sum weights: 1.000002 
round 3 sum weights: 1.000001 
round 4 sum weights: 0.999999 
round 5 sum weights: 0.999998 
round 6 sum weights: 0.999999 
round 7 sum weights: 0.999999 
All non-selected update_norm == 0: TRUE 
All non-selected client_weight == 0: TRUE
All checks pass. Sums are ~1.0 (with minor round-off from 6-decimal rounding). Let me also verify edge cases for hidden variant and test a run without a bias CSV:
bash
cd /app && rm -rf outputs/*.csv outputs/*.json outputs/*.png
FEDSIMG_SEED=123 TASK_VARIANT=hidden FEDSIMG_ALPHA=0.3 FEDSIMG_NOISE_SCALE=3.0 FEDSIMG_SIGNAL_SCALE=0.2 FEDSIMG_TRIM_K=3 FEDSIMG_BIAS_STRENGTH=0.5 FEDSIMG_OUTPUT_DIR=outputs Rscript analysis.R 2>&1 | tail -10
echo "---"
cat /app/outputs/analysis_summary.json
output
---
{
  "task_variant": "hidden",
  "seed": 123,
  "env": {
    "FEDSIMG_ALPHA": "0.3",
    "FEDSIMG_NOISE_SCALE": "3",
    "FEDSIMG_SIGNAL_SCALE": "0.2",
    "FEDSIMG_TRIM_K": "3",
    "FEDSIMG_BIAS_STRENGTH": "0.5",
    "FEDSIMG_CLIENT_BIAS_CSV": ""
  },
  "simulation_meta": {
    "n_clients": 100,
    "n_byzantine": 10,
    "clients_per_round": 20,
    "n_rounds": 8,
    "param_dim": 256,
    "trim_k": 3
  },
  "byzantine_client_ids": [0, 1, 2, 3, 4, 5, 6, 7, 8, 9],
  "final_metrics": {
    "trimmed_mean_accuracy": 0.972687,
    "fedavg_accuracy": 0.954693,
    "delta": 0.017994
  },
  "provenance": {
    "manifest_md5": "475adf00a65314160823670bdaef093c",
    "selection_histogram": [1, 0, 2, 3, 3, 0, 1, 1, 3, 3, 1, 2, 2, 2, 1, 0, 1, 2, 0, 2, 2, 1, 1, 1, 1, 3, 2, 3, 1, 1, 2, 0, 5, 2, 3, 0, 1, 3, 0, 3, 2, 1, 1, 0, 2, 1, 1, 2, 0, 1, 1, 2, 2, 2, 2, 2, 4, 1, 2, 3, 4, 3, 3, 3, 1, 1, 3, 1, 2, 0, 3, 4, 0, 1, 1, 2, 1, 1, 0, 0, 2, 0, 0, 3, 1, 2, 3, 2, 0, 4, 1, 0, 1, 1, 3, 1, 2, 1, 1, 1]
  }
}
The hidden variant also works. Let me also do a quick sanity check on the R numeric to JSON conversion (to make sure values are written full precision):
bash
cd /app && Rscript -e '
# Verify JSON numeric precision matches CSV (full precision, no lossy rounding)
m <- read.csv("outputs/metrics_by_round.csv", stringsAsFactors=FALSE)
last_round <- max(m$round)
fed <- m[m$round == last_round & m$method == "fedavg", "accuracy"]
tm <- m[m$round == last_round & m$method == "trimmed_mean", "accuracy"]

# Parse JSON raw text to see exact values
j <- readLines("outputs/analysis_summary.json")
cat(grep("_accuracy|delta", j, value = TRUE), sep="\n")

cat("CSV fed (as printed):", format(fed, nsmall = 6), "\n")
cat("CSV tm (as printed):", format(tm, nsmall = 6), "\n")
cat("delta = tm - fed =", format(tm - fed, nsmall = 6), "\n")
'
output
"trimmed_mean_accuracy": 0.972687,
    "fedavg_accuracy": 0.954693,
    "delta": 0.017994
CSV fed (as printed): 0.954693 
CSV tm (as printed): 0.972687 
delta = tm - fed = 0.017994
JSON values match CSV exactly. Let me run one more test to ensure the output gets regenerated properly even if existing stale files are there:
bash
cd /app && touch outputs/metrics_by_round.csv -d "2020-01-01"
ls -la outputs/metrics_by_round.csv
FEDSIMG_SEED=42 FEDSIMG_CLIENT_BIAS_CSV=/app/example_client_bias.csv TASK_VARIANT=public FEDSIMG_OUTPUT_DIR=outputs Rscript analysis.R 2>&1 | tail -5
ls -la outputs/metrics_by_round.csv
output
-rw-r--r-- 1 h2tagent h2tagent 1733 Jan  1  2020 outputs/metrics_by_round.csv
-rw-r--r-- 1 h2tagent h2tagent 1739 May 28 23:10 outputs/metrics_by_round.csv
Outputs get freshly overwritten on each run. Final summary of key fixes made to `/app/analysis.R`: 1. **Byzantine IDs**: Now `0:(n_byz-1)` (fixed_lowest_client_ids per manifest). 2. **Entropy**: Natural log (`log`) instead of `log10`. 3. **Byzantine attack**: Uses `-u_clean + rnorm(param_dim, 0, noise_scale)` exactly as manifest specifies. 4. **Trimmed mean**: Coordinate-wise (not by norm ranking). 5. **FedAvg weighting**: Per-round weights `n_train/sum(selected n_train)` (summing to 1). 6. **byzantine_audit**: Uses submitted update norms, zero for non-selected; client_weight is the round-specific FedAvg weight. 7. **client_updates_clean**: `u_submitted` is now the attacked update (was erroneously set to `u_clean`). 8. **Honest update**: Uses the bias-CSV rows when provided, falling back to empirical mix for any missing clients. 9. **All env vars honored**: `FEDSIMG_ALPHA`, `FEDSIMG_NOISE_SCALE`, `FEDSIMG_SIGNAL_SCALE`, `FEDSIMG_TRIM_K`, `FEDSIMG_BIAS_STRENGTH`, `FEDSIMG_CLIENT_BIAS_CSV`. 10. **dirichlet_gammas.allocated_count**: Pre-repair Hamilton allocation (tracked separately from post-repair partition). 11. **partition_summary.top_label_share**: Now uses client's `n_train` as denominator (was `per_class`). 12. **analysis_summary.json**: Includes `trim_k` in `simulation_meta`, all 6 required env keys, `delta = tm - fed` (signed, not abs). JSON values derived from CSVs read back, preserving full precision. `selection_histogram` length 100 matching per-client selection counts. 13. **read_bias_csv**: Handles partial coverage (e.g., only 5 rows in example CSV); normalizes rows (not columns) to sum to 1.
Final diff , what the agent changed

No file changes, the agent left the workspace untouched.

Verifier output , the proof behind the reward
tests/test.sh
# SyncVals normalized verifier summary
# task: fedavg-federated-noniid-mnist
# attempt: 2  status: completed  raw_score: 0.0
# reward rule: binary: score 0.0 != 1.0
# => reward = 0.0  (FAIL)
#
# Note: these tasks score via an external hidden grader; no pytest/verifier
# block is embedded in the agent transcript. The block below is the last
# sizable tool-output captured in the run (supporting evidence).
----------------------------------------------------------------------
---
{
  "task_variant": "hidden",
  "seed": 123,
  "env": {
    "FEDSIMG_ALPHA": "0.3",
    "FEDSIMG_NOISE_SCALE": "3",
    "FEDSIMG_SIGNAL_SCALE": "0.2",
    "FEDSIMG_TRIM_K": "3",
    "FEDSIMG_BIAS_STRENGTH": "0.5",
    "FEDSIMG_CLIENT_BIAS_CSV": ""
  },
  "simulation_meta": {
    "n_clients": 100,
    "n_byzantine": 10,
    "clients_per_round": 20,
    "n_rounds": 8,
    "param_dim": 256,
    "trim_k": 3
  },
  "byzantine_client_ids": [0, 1, 2, 3, 4, 5, 6, 7, 8, 9],
  "final_metrics": {
    "trimmed_mean_accuracy": 0.972687,
    "fedavg_accuracy": 0.954693,
    "delta": 0.017994
  },
  "provenance": {
    "manifest_md5": "475adf00a65314160823670bdaef093c",
    "selection_histogram": [1, 0, 2, 3, 3, 0, 1, 1, 3, 3, 1, 2, 2, 2, 1, 0, 1, 2, 0, 2, 2, 1, 1, 1, 1, 3, 2, 3, 1, 1, 2, 0, 5, 2, 3, 0, 1, 3, 0, 3, 2, 1, 1, 0, 2, 1, 1, 2, 0, 1, 1, 2, 2, 2, 2, 2, 4, 1, 2, 3, 4, 3, 3, 3, 1, 1, 3, 1, 2, 0, 3, 4, 0, 1, 1, 2, 1, 1, 0, 0, 2, 0, 0, 3, 1, 2, 3, 2, 0, 4, 1, 0, 1, 1, 3, 1, 2, 1, 1, 1]
  }
}

Reproduce this trial: git checkout 2f94510 && PYTHONPATH=src python3 scripts/build_site.py , then open trial/trial_f2b4372ed3004c41. Re-running the agent live requires EVAL_PLATFORM_ENABLE_OAUTH_SMOKE=1 and is non-deterministic.

Trial trial_f2b4372ed3004c41 · verifier authoritative; classifier explanatory.