# STEP

Utility/GeneralEvaluates a STEP function via a cubic polynomial approximation.

## Use

This function can be called by any user-defined subroutine.

## Format

Fortran Calling Syntax
CALL STEP (X, X0, H0, X1, H1, IORD, VALUE, ERRFLG)
C/C++ Calling Syntax
c_step(x, x0, h0, x1, h1, iord, value, errflg)
Python Calling Syntax
[value, errflg] = py_step(x, x0, h0, x1, h1, irod)
MATLAB Calling Syntax
[value, errflg] = m_step(x, x0, h0, x1, h1, irod)

## Attributes

X
[double precision]
The independent variable. For example, to specify time as the independent variable, specify X as TIME.
X0
[double precision]
The X value at which the STEP function begins.
H0
[double precision]
The value of the STEP function at X0
X1
[double precision]
The X value at which the STEP function ends.
H1
[double precision]
The value of the STEP function at X1.
IORD
[integer]
The order of the derivative that STEP has to return. Order can be 0, 1 or 2.

## Output

Value
[integer]
A value that the subroutine returns.
Errflg
[logical]
A (true or false) variable that STEP returns to the calling subroutine. If STEP detects an error while calling the subroutine, it sets the error flag to true.