pdf — Evaluate a fitted or named probability distribution density or probability mass function.
pdf(pd,x) evaluates the density or probability mass function for a ProbabilityDistribution object returned by fitdist. pdf(distname,x,params...) evaluates supported named distributions directly.
Syntax
y = pdf(pd, x)
y = pdf(distname, x, params)Inputs
| Name | Type | Required | Default | Description |
|---|---|---|---|---|
pd | Any | Yes | — | ProbabilityDistribution object returned by fitdist. |
x | NumericArray | Yes | — | Sample data or evaluation points. |
distname | StringScalar | Yes | — | Distribution name. |
NameValue | Any | Variadic | — | Name-value options. |
Returns
| Name | Type | Description |
|---|---|---|
y | NumericArray | Distribution function values. |
Errors
| Identifier | When | Message |
|---|---|---|
RunMat:fitdist:InvalidArgument | Sample data, distribution name, options, or evaluation inputs are malformed. | fitdist: invalid argument |
RunMat:fitdist:Numerical | Distribution parameter estimation fails to converge or is ill-conditioned. | fitdist: numerical failure |
RunMat:fitdist:Internal | RunMat cannot construct distribution outputs. | fitdist: internal error |
How pdf works
pdmust be a fitted distribution object returned byfitdist, ordistnamemust name a supported distribution.- Supported named distributions are
"Normal","Exponential","Lognormal","Gamma","Weibull", and"Poisson"with their standard scalar parameters. xand named-distribution parameters may be scalar or mutually broadcast-compatible numeric arrays; the output has their broadcast shape.- Typed-integer evaluation points and distribution parameters are independent RunMat extensions and reject values that cannot cross the binary64 probability boundary exactly.
- Continuous distributions return probability densities. Poisson returns probability mass values at integer support points and zero outside the support.
Examples
Evaluate a fitted normal density
pd = fitdist([1;2;3], "Normal"); y = pdf(pd, 2)Evaluate a named normal density
y = pdf("Normal", 0, 0, 1)Using pdf with coding agents
Open a RunMat example with live inputs, then ask the agent to explain how pdf changes the result.
Run a small pdf example, explain the result, then change one input and compare the output.
FAQ
Can pdf evaluate by distribution name?⌄
Yes. The named overload supports normal, exponential, lognormal, gamma, Weibull, and Poisson with scalar parameters. Distribution-specific helpers such as normpdf remain available.
Related Stats functions
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 · prctile · quantile · refline · rmse · skewness · tabulate · tcdf · tiedrank · tinv · tpdf · ttest2 · wblinv
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
Random
binornd · bootstrp · datasample · dividerand · exprnd · gamrnd · lhsdesign · mvnrnd · normrnd · random · randsample · rng · trnd · unidrnd · unifrnd · wblrnd
Hist
Open-source implementation
Unlike proprietary runtimes, every RunMat function is open-source. Read exactly how pdf is executed, line by line, in Rust.
- View the source for pdf in Rust on GitHub
- Learn how the RunMat runtime works
- Found a bug? Open an issue with a minimal reproduction.
About RunMat
RunMat is an open-source runtime that executes MATLAB-syntax code blazing on any GPU. It is licensed under the Apache 2.0 license.
- RunMat automatically optimizes your math for GPU execution on Apple, Nvidia, and AMD hardware. No code changes needed. Simulations that took hours now take minutes.
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