[BUG]Single subject stats model crashes during contrast specification

[jwrschultz]

Is there an existing issue for this?

• I have searched the existing issues

Operating system

• Linux
• Mac
• Windows

Operating system version

• Mac OS Version 12 "monterey"

SPM 12 version

• 7771
• 7487
• 7219

Platform

• MATLAB
• Octave

Platform version

• MATLAB 2024b

bidspm version

v3.1.0

bidspm branch / commit number

• v4.0.0dev
• main 'b1b767ee'

Expected Behavior

I expected dummy contrasts to be specified after model estimation. Instead I get an error.

BIDS stats model

{
  "Name": "default_fedtask_model",
  "BIDSModelVersion": "1.0.0",
  "Description": "default BIDS stats model for fedtask task",
  "Input": {
    "task": ["fedtask"],
    "space": ["MNI152NLin2009cAsym"]
  },
  "Nodes": [
    {
      "Level": "Run",
      "Name": "run",
      "GroupBy": [
        "run",
        "subject"
      ],
      "Transformations": {
        "Transformer": "",
        "Instructions": [
          {
            "Name": "",
            "Inputs": [""]
          }
        ]
      },
      "Model": {
        "X": [
          "trial_type.H_post",
          "trial_type.H_pre",
          "trial_type.congruent",
          "trial_type.control",
          "trial_type.incongruent",
          "trial_type.not_updated",
          "trial_type.updated",
          "1",
          "trans_?",
          "rot_?",
          "non_steady_state_outlier*",
          "motion_outlier*"
        ],
        "Type": "glm",
        "HRF": {
          "Variables": [
            "trial_type.H_post",
            "trial_type.H_pre",
            "trial_type.congruent",
            "trial_type.control",
            "trial_type.incongruent",
            "trial_type.not_updated",
            "trial_type.updated"
          ],
          "Model": "spm"
        },
        "Options": {
          "HighPassFilterCutoffHz": 0.008,
          "Mask": {
            "desc": ["brain"],
            "suffix": ["mask"]
          }
        },
        "Software": {
          "SPM": {
            "SerialCorrelation": "FAST",
            "InclusiveMaskingThreshold": 0.8
          }
        }
      },
      "Contrasts": [
        {
          "Name": "",
          "ConditionList": [""],
          "Weights": [""],
          "Test": "t"
        }
      ],
      "DummyContrasts": {
        "Test": "t",
        "Contrasts": [
          "trial_type.H_post",
          "trial_type.H_pre",
          "trial_type.congruent",
          "trial_type.control",
          "trial_type.incongruent",
          "trial_type.not_updated",
          "trial_type.updated"
        ]
      }
    },
    {
      "Level": "Subject",
      "Name": "subject",
      "GroupBy": [
        "subject",
        "contrast"
      ],
      "Model": {
        "X": [1],
        "Type": "glm"
      },
      "DummyContrasts": {
        "Test": "t"
      }
    },
    {
      "Level": "Dataset",
      "Name": "dataset",
      "GroupBy": ["contrast"],
      "Model": {
        "X": [1],
        "Type": "glm"
      },
      "DummyContrasts": {
        "Test": "t"
      }
    }
  ],
  "Edges": [
    {
      "Source": "run",
      "Destination": "subject"
    },
    {
      "Source": "subject",
      "Destination": "dataset"
    }
  ]
}

Current Behavior & Error message

% copy the error you got below
% before the three backticks (```)

Conversion to double from cell is not possible.

Error in specifyDummyContrasts>addSubjectLevelContrastBasedOnPreviousLevels (line 103)
    C.C(end, regIdx{iCdt}) = thisContrast.Weights(iCdt);

Error in specifyDummyContrasts (line 77)
        C = addSubjectLevelContrastBasedOnPreviousLevels(model, thisContrast);

Error in specifyContrasts (line 64)
    [contrasts, counter] = specifyDummyContrasts(model, node, contrasts, counter);

Error in setBatchSubjectLevelContrasts (line 42)
    contrasts = specifyContrasts(bm, SPM);

Error in bidsFFX (line 120)
        matlabbatch = setBatchSubjectLevelContrasts(matlabbatch, opt, subLabel, nodeName);

Error in cliStats>runContrasts (line 127)
    bidsFFX('contrasts', opt);

Error in cliStats (line 86)
        runContrasts(isSubjectLevel, opt, nodeName, concatenate);

Error in bidspm>executeAction (line 86)
      cliStats(varargin{2:end});

Error in bidspm (line 26)
    returnCode = executeAction(action, varargin{:});

Error in test_bidspm (line 48)
bidspm(bids_dir, output_dir, 'subject', ...

Anything else?

error_2026-02-05T13-20.log