# Komplot function plotting (fortran only)

#### Function plotting, only in fortran

Subroutine functions with one parameter can be visualized by the routines in this section. DLAB, NP, XFROM, XTO, FX are common parameters.

DLAB (string) is a data label

NP is the number of equidistant X-coordinates from XFROM to XTO, the increase per coordinate = (XTO-XFROM)/(NP-1), NP>= 2.

FX is a real function subroutine of one REAL variable, used to compute the Y-coordinates belonging to the NP X-coordinates. Must be declared: `EXTERNAL FX `

#### Lines

`subroutine F_POLYLINE(DLAB, NP, XFROM, XTO, FX)`
Points connected as polyline, NP>=2.
`subroutine F_DISJOINT_LINE(DLAB, NP, XFROM, XTO, FX)`
Points connected as disjoint line, NP>=2.

#### Interpolation

`subroutine F_CURVE(DLAB, NP, XFROM, XTO, FX)`
Points connected by smooth interpolated line, NP>=3.
( `subroutine F_SPLINE(DLAB, NP, XFROM, XTO, FX) `)

#### Markers

`subroutine F_MARKERS(DLAB, NP, XFROM, XTO, FX, ISYM)`
Points marked by symbol defined by ISYM

#### Example

```
```      program yxx
c make graph of y = x*x from 0.0 ... 10.0
EXTERNAL FX
REAL XFROM, XTO
XFROM = 0.0
XTO   = 10.0
call FRAME (10., XFROM, XTO,8., 0., 0., 'X', 'Y', 'Function')
call F_CURVE (21, XFROM, XTO, FX, 'y = x*x')
end

function FX(x)
FX = x*x
end
```

```