movvar — Compute moving variances in MATLAB and RunMat.
movvar(A,k) computes variances over a sliding window of length k along the first non-singleton dimension.
Syntax
M = movvar(A, k)
M = movvar(A, k, w)
M = movvar(A, k, w, dim)
M = movvar(A, k, nanflag)
M = movvar(A, k, w, nanflag)
M = movvar(A, k, w, dim, nanflag)All supported movvar forms
M = movvar(A, k)
M = movvar(A, k, w)
M = movvar(A, k, w, dim)
M = movvar(A, k, nanflag)
M = movvar(A, k, w, nanflag)
M = movvar(A, k, w, dim, nanflag)
M = movvar(A, k, Name, Value)
M = movvar(A, k, w, Name, Value)
M = movvar(A, k, w, nanflag, Name, Value)
M = movvar(A, k, w, dim, Name, Value)
M = movvar(A, k, w, dim, nanflag, Name, Value)Inputs
| Name | Type | Required | Default | Description |
|---|---|---|---|---|
A | Any | Yes | — | Input numeric, logical, or gpuArray data. |
k | NumericArray | Yes | — | Window length or two-element [kb kf] backward/forward window. |
w | NumericArray | No | 0 | Normalization flag: 0 for sample normalization, 1 for population normalization. |
dim | NumericArray | No | — | Dimension along which to move the window. |
nanflag | StringScalar | No | "includenan" | NaN handling mode: "includenan" or "omitnan". |
NameValue | Any | Variadic | — | Name-value options, including "Endpoints". |
Returns
| Name | Type | Description |
|---|---|---|
M | NumericArray | Moving-window reduction result. |
Errors
| Identifier | When | Message |
|---|---|---|
RunMat:movvar:InvalidArgument | Window length, dimension, nanflag, or name-value options are invalid. | moving window: invalid argument |
RunMat:movvar:InvalidInput | Input values cannot be converted to a supported moving-window domain. | moving window: invalid input |
RunMat:movvar:Internal | Moving-window execution fails due to allocation, provider, or shape operations. | moving window: internal failure |
How movvar works
kmay be a positive scalar window length or a two-element[kb kf]backward/forward window.movvar(A,k,0)uses sample normalization byN-1, except singleton windows divide byN; this is the default.movvar(A,k,1)uses population normalization byN.- Pass an explicit normalization flag before
dim, for examplemovvar(A,k,0,2), to move along a chosen dimension. 'includenan'is the default;'omitnan'and'omitmissing'skip NaN values inside each window.'Endpoints'supports'shrink'(default),'discard','fill', and numeric scalar fill values.'SamplePoints', spuses a strictly increasing numeric point vector for irregular moving windows. With sample points, RunMat currently supports shrink endpoints.- This implementation covers numeric, logical, complex, and gpuArray inputs; table/timetable
DataVariablesforms are tracked separately.
Example
Moving variance across columns
A = [4 8 6];
M = movvar(A,3)Expected output:
M = [8 4 2]Using movvar with coding agents
Open a RunMat example with live inputs, then ask the agent to explain how movvar changes the result.
Run a small movvar example, explain the result, then change one input and compare the output.
Related Math functions
Reduction
all · any · bounds · cummax · cummin · cumprod · cumsum · cumtrapz · diff · gradient · max · maxk · mean · median · min · mink · movmax · movmean · movmedian · movmin · movprod · movstd · movsum · nnz · prod · rms · std · sum · trapz · var
Elementwise
abs · angle · bsxfun · complex · conj · double · erf · erfcinv · exp · expm1 · factorial · flintmax · gamma · gammaln · heaviside · hypot · idivide · imag · intmax · intmin · ldivide · log · log10 · log1p · log2 · minus · nextpow2 · plus · pow2 · power · rdivide · real · realmax · realmin · realsqrt · rescale · sign · single · sqrt · swapbytes · times · typecast · uint16 · uint32 · uint8
Trigonometry
acos · acosh · asin · asinh · atan · atan2 · atanh · cos · cosd · cosh · cospi · deg2rad · pol2cart · rad2deg · sin · sind · sinh · sinpi · tan · tand · tanh
Structure
bandwidth · isdiag · ishermitian · issymmetric · istril · istriu · symrcm
Signal
blackman · butter · buttord · cheb2ord · conv · conv2 · deconv · downsample · envelope · filter · filtfilt · fir1 · freqz · gauspuls · hamming · hann · hilbert · periodogram · pulstran · pwelch · rectpuls · resample · sawtooth · sinc · spectrogram · square · tripuls · unwrap · upsample · zplane
Optim
coneprog · fminbnd · fminunc · fsolve · fzero · integral · linprog · lsqcurvefit · lsqnonlin · optimoptions · optimset · quad · secondordercone
Ops
cross · ctranspose · dot · mldivide · mpower · mrdivide · mtimes · pagemtimes · pagetranspose · trace · transpose
Open-source implementation
Unlike proprietary runtimes, every RunMat function is open-source. Read exactly how movvar is executed, line by line, in Rust.
- View the source for movvar 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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