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 native single storage; integer and other numeric or logical inputs return double values. Every integer data or bound value must be exactly representable at this explicit floating rescaling boundary rather than being silently rounded.
- 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 · 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
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 · 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 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.