MAT Files

ccalc can read MATLAB Level 5/7 .mat files using load. This lets you exchange data with MATLAB, Octave, SciPy, and any other tool that writes the standard MAT format.

Requires the mat feature:

cargo build --release --features mat

Without this flag, calling load('*.mat') returns an error message explaining how to enable the feature.

Loading a MAT file

Assignment form

data = load('file.mat') reads all variables from the file and returns a Struct whose fields are the variable names.

data = load('results.mat');

data.score        % scalar variable from the file
data.readings     % matrix variable from the file
data.label        % char-array variable from the file
data.sensor.id    % struct field — nested access works directly

Access the shape of a loaded matrix:

fprintf('%dx%d\n', size(data.A, 1), size(data.A, 2))

Bare form

load('file.mat') (without an assignment) injects all variables directly into the current workspace:

load('results.mat')

% All variables are now in scope:
score
readings
sensor.gain

This is equivalent to the assignment form followed by assigning each field to a workspace variable.

Type mapping

Complex and sparse matrices are not yet supported.

Working with loaded data

Scalar

data = load('results.mat');
s = data.score;
fprintf('score = %g,  score^2 = %g\n', s, s^2)

Matrix

A = data.A;
fprintf('A is %dx%d\n', size(A, 1), size(A, 2))
fprintf('trace(A''*A) = %.1f\n', trace(A'*A))

Char array

lbl = data.label;
fprintf('label = %s\n', upper(lbl))

Struct fields

sen = data.sensor;
scaled = data.readings * sen.gain;
fprintf('scaled mean = %.2f\n', mean(scaled))

Saving MAT files

Writing .mat files is not yet supported. save('out.mat', ...) returns an informative error. Use save without a .mat extension (or ws) to persist workspace variables in ccalc’s native TOML format.

Example

The examples/mat/mat.calc file demonstrates all MAT-file features:

cargo run --release --features mat -- examples/mat/mat.calc

It covers: assignment form, scalar arithmetic, row-vector statistics, matrix algebra, char-array built-ins, struct field access, bare workspace merge, and a simple signal-analysis routine.

Generating the fixture

The example uses examples/mat/fixtures/sample.mat, which can be regenerated with:

cargo test --features mat create_example_fixture -- --ignored