vpa — Evaluate scalar symbolic or numeric input as a symbolic decimal.
vpa(x) converts a scalar symbolic or numeric input to a scalar symbolic decimal literal using the current digits setting. vpa(x, d) uses d significant decimal digits. Exact symbolic rationals are expanded exactly; ordinary numeric inputs are rendered from the numeric value supplied by the script.
Syntax
S = vpa(x)
S = vpa(x, d)Inputs
| Name | Type | Required | Default | Description |
|---|---|---|---|---|
x | Any | Yes | — | Scalar symbolic or numeric input. |
d | NumericScalar | No | digits | Number of significant decimal digits. |
Returns
| Name | Type | Description |
|---|---|---|
S | Any | Scalar symbolic variable-precision value or expression. |
Errors
| Identifier | When | Message |
|---|---|---|
RunMat:vpa:ArgCount | More than one optional precision argument is supplied. | vpa: too many input arguments |
RunMat:vpa:InvalidInput | Input cannot be represented as a scalar symbolic expression. | vpa: expected a scalar symbolic, numeric, logical, or numeric text input |
RunMat:vpa:InvalidDigits | The requested precision is not an integer in the supported range. | vpa: expected a positive integer digit count |
How vpa works
- The default precision is controlled by
digitsand starts at 32 significant digits. - Exact rational symbolic inputs such as
sym('1/3')are expanded and rounded with the requested significant digits. - Numeric scalar inputs are converted to symbolic decimal literals from their existing numeric value at the requested display precision.
- Scalar values from every integer class are lifted directly into exact arbitrary-precision integer storage, including
int64anduint64extrema. - Integer precision controls are decoded exactly; noninteger floating controls are rounded to the nearest integer before the supported range is checked.
- Nonconstant symbolic variables remain symbolic.
- RunMat currently represents scalar symbolic expressions; array-valued symbolic containers and the documented
BoostPrecisionoption are not implemented.
Examples
Render numeric pi at 50 digits
vpa(pi, 50)Expected output:
3.141592653589793...Evaluate an exact rational
vpa(sym('1/3'), 20)Expected output:
0.33333333333333333333Using vpa with coding agents
Open a RunMat example with live inputs, then ask the agent to explain how vpa changes the result.
Run a small vpa example, explain the result, then change one input and compare the output.
FAQ
Does vpa return a double?⌄
No. It returns a scalar symbolic value so formatting and downstream symbolic operations can preserve the decimal literal.
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 · 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
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 vpa is executed, line by line, in Rust.
- View the source for vpa 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.