unifrnd — Generate uniform random samples on interval [a, b) with MATLAB-compatible size handling.
unifrnd(a, b, ...) draws pseudorandom samples from a continuous uniform distribution over [a, b). It follows MATLAB-compatible parameter broadcasting and optional size-argument forms.
Syntax
r = unifrnd(a, b)
r = unifrnd(a, b, sz)
r = unifrnd(a, b, sz1, sz2, ...)Inputs
| Name | Type | Required | Default | Description |
|---|---|---|---|---|
a | Any | Yes | — | Lower bound parameter. |
b | Any | Yes | — | Upper bound parameter (must be > a). |
sz | Any | Yes | — | Size scalar or size vector argument. |
sz | Any | Variadic | — | Dimension extents for output shape. |
Returns
| Name | Type | Description |
|---|---|---|
r | NumericArray | Random sample array from uniform distribution. |
Errors
| Identifier | When | Message |
|---|---|---|
RunMat:unifrnd:LowerBoundMustBeLessThanUpperBound | a is greater than or equal to b. | unifrnd: a must be less than b |
RunMat:unifrnd:InvalidArgument | Input parameters or size arguments are missing or malformed. | unifrnd: invalid argument |
RunMat:unifrnd:Internal | Internal conversion/allocation/provider decode fails. | unifrnd: internal operation failed |
How unifrnd works
unifrnd(a, b)returns a scalar double drawn fromUniform(a, b).unifrnd(a, b, n)returns ann × nmatrix of samples.unifrnd(a, b, m, n)returns anm × nmatrix of samples.unifrnd(a, b, sz)accepts a size vector and returns an array with shapesz.aandbmust be scalar single or double values on the compatibility surface.- Native typed-integer bounds are independently gated RunMat extensions and must be exactly representable before entering binary64 sampling.
amust be less thanb;unifrnderrors ifa >= b.- Native typed-integer size controls are a separately gated RunMat extension and are decoded exactly as structural extents.
- The currently implemented scalar-parameter path returns double output. Complete documented single-parameter class propagation and array parameter broadcasting remain implementation gaps.
Examples
Single sample from Uniform(2, 5)
rng(0);
r = unifrnd(2, 5)Matrix of random values between -1 and 1
rng(0);
X = unifrnd(-1, 1, 2, 3)Monte Carlo samples for uncertain input bounds
rng(0);
low = 10; high = 20;
samples = unifrnd(low, high, 1, 5)Specifying dimensions with a size vector
rng(0);
T = unifrnd(0, 100, [2 3])Using unifrnd with coding agents
Open a RunMat example with live inputs, then ask the agent to explain how unifrnd changes the result.
Run a small unifrnd example, explain the result, then change one input and compare the output.
FAQ
Are the bounds inclusive?⌄
RunMat generates samples on the half-open interval [a, b): values can be equal to a, but are always strictly less than b.
What is the workaround if unifrnd is unavailable?⌄
unifrnd(a, b) is mathematically equivalent to a + (b - a) * rand(). For arrays, use a + (b - a) * rand(sz) with the same requested size.
Why must a be less than b?⌄
A continuous uniform distribution needs a positive-width interval. unifrnd raises an error if a >= b to catch invalid bounds early.
What use cases does unifrnd support?⌄
Common uses include Monte Carlo sampling, randomized initial conditions, parameter sweeps over bounded ranges, simulation inputs, and continuous random perturbations.
Does unifrnd fuse with other operations?⌄
No. Random generation is excluded from fusion planning to preserve statistical properties.
How do I control reproducibility?⌄
Use rng before calling unifrnd to seed the global generator.
Related Stats functions
Random
binornd · bootstrp · datasample · dividerand · exprnd · gamrnd · lhsdesign · mvnrnd · normrnd · random · randsample · rng · trnd · unidrnd · wblrnd
Ml
bayesopt · classify · confusionmat · crossvalind · cvpartition · fitclinear · fitctree · fitlm · kmeans · knnsearch · lasso · lassoglm · linkage · lscov · mnrfit · optimizableVariable · pdist · pdist2 · perfcurve · predict · regress · ridge · squareform · test · training · tsne
Summary
binocdf · boxplot · cdf · cdfplot · chi2cdf · corr · corrcoef · corrcov · cov · cov2corr · dummyvar · ecdf · filloutliers · fitdist · geomean · grpstats · harmmean · icdf · isoutlier · kstest · kurtosis · lsline · mad · mode · nanmax · normalize · normcdf · norminv · normpdf · onehotdecode · onehotencode · pdf · prctile · quantile · refline · rmse · skewness · tabulate · tcdf · tiedrank · tinv · tpdf · ttest2 · wblinv
Hist
Open-source implementation
Unlike proprietary runtimes, every RunMat function is open-source. Read exactly how unifrnd is executed, line by line, in Rust.
- View the source for unifrnd in Rust on GitHub
- Learn how the RunMat runtime works
- Found a bug? Open an issue with a minimal reproduction.
About RunMat
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