rescale — Scale the range of array elements in MATLAB and RunMat.
R = rescale(A) scales array values to [0,1] using the minimum and maximum over all elements of A. rescale(A,l,u) scales to [l,u], and InputMin/InputMax name-value options override the input range and clip values before scaling.
Syntax
R = rescale(A)
R = rescale(A, l, u)
R = rescale(A, Name, Value)
R = rescale(A, l, u, Name, Value)Inputs
| Name | Type | Required | Default | Description |
|---|---|---|---|---|
A | Any | Yes | — | Input numeric or logical array. |
l | NumericArray | No | 0 | Lower bound for the output interval. |
u | NumericArray | No | 1 | Upper bound for the output interval. |
Name | StringScalar | No | — | Name-value option name: "InputMin" or "InputMax". |
Value | Any | No | — | Name-value option value. |
Returns
| Name | Type | Description |
|---|---|---|
R | NumericArray | Scaled output array. |
Errors
| Identifier | When | Message |
|---|---|---|
RunMat:rescale:InvalidArgument | Arguments, name-value pairs, interval bounds, or input range bounds are invalid. | rescale: invalid argument |
RunMat:rescale:InvalidInput | Input values cannot be converted to real numeric or logical arrays. | rescale: invalid input |
RunMat:rescale:SizeMismatch | A bound array cannot be implicitly expanded with the input array. | rescale: size mismatch |
RunMat:rescale:Internal | Tensor construction, allocation, or GPU gather fails internally. | rescale: internal error |
How rescale works
- The default range is computed from all elements of
A, not independently by row or column. - The output interval bounds
landu, and theInputMinandInputMaxvalues, can be scalars or arrays that are implicitly expandable withA. - Supplying vector
InputMinandInputMaxvalues supports independent row-wise or column-wise scaling while preserving MATLAB implicit expansion behavior. - Values below
InputMinare clipped toInputMin; values aboveInputMaxare clipped toInputMaxbefore scaling. - Constant input ranges return the lower output bound, or
NaNwhen the output interval containsInf. - Single-precision tensor inputs preserve single dtype metadata; other numeric and logical inputs return double values.
- NaN values are omitted when computing the default input range, and NaN input elements remain NaN in the corresponding output positions. All-NaN inputs produce NaN outputs.
- Complex, string, cell, struct, object, and function-handle inputs are rejected.
Examples
Scale a vector to the unit interval
A = 1:5;
R = rescale(A)Expected output:
R = [0 0.25 0.5 0.75 1]Scale a vector to a custom interval
A = 1:5;
R = rescale(A,-1,1)Expected output:
R = [-1 -0.5 0 0.5 1]Clip to an input range before scaling
A = [-30 1 2 3 4 5 70];
R = rescale(A,"InputMin",1,"InputMax",5)Expected output:
R = [0 0 0.25 0.5 0.75 1 1]Scale matrix columns independently
A = [0.4 -4; 0.5 -5; 0.9 9; 0.2 1];
R = rescale(A,"InputMin",min(A),"InputMax",max(A))Expected output:
R = [0.2857 0.0714; 0.4286 0; 1 1; 0 0.4286]Using rescale with coding agents
Open a RunMat example with live inputs, then ask the agent to explain how rescale changes the result.
Run a small rescale example, explain the result, then change one input and compare the output.
FAQ
Does rescale(A) operate column-wise?⌄
No. The default range uses min(A(:)) and max(A(:)) across all elements. Use vector InputMin and InputMax values, such as min(A) and max(A), for independent column scaling.
What happens when all input values are equal?⌄
RunMat returns the lower output bound, matching MATLAB. If the requested output interval contains Inf, the result is NaN.
Can InputMin and InputMax be arrays?⌄
Yes. They may be scalars, vectors, matrices, or N-D arrays that are compatible with A under MATLAB implicit expansion rules.
Does RunMat keep rescale(gpuArray(...)) on the GPU?⌄
Yes. The current implementation may use a host round trip internally for documented argument forms, but it uploads the result back to the active provider when any operand is a gpuArray.
Related Math functions
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 · sign · single · sqrt · swapbytes · times · uint32
Trigonometry
acos · acosh · asin · asinh · atan · atan2 · atanh · cos · cosd · cosh · cospi · deg2rad · pol2cart · rad2deg · sin · sind · sinh · sinpi · tan · tand · tanh
Reduction
all · any · bounds · cummax · cummin · cumprod · cumsum · cumtrapz · diff · gradient · max · maxk · mean · median · min · mink · movmax · movmean · movmedian · movmin · movprod · movstd · movsum · movvar · nnz · prod · rms · std · sum · trapz · var
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 · 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 rescale is executed, line by line, in Rust.
- View the source for rescale 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.
- Start running code in seconds. RunMat runs in the browser, on the desktop, or from the CLI. No license server, no IT ticket.