The Alternative Csound Reference Manual
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# GEN07

GEN07 -- Constructs functions from segments of straight lines.

## Description

Constructs functions from segments of straight lines.

## Syntax

f # time size 7 a n1 b n2 c ...

## Initialization

size -- number of points in the table. Must be a power of 2 or power-of-2 plus 1 (see f statement).

a, b, c, etc. -- ordinate values, in odd-numbered pfields p5, p7, p9, . . .

n1, n2, etc. -- length of segment (no. of storage locations), in even-numbered pfields. Cannot be negative, but a zero is meaningful for specifying discontinuous waveforms (e.g. in the example below). The sum n1 + n2 + .... will normally equal size for fully specified functions. If the sum is smaller, the function locations not included will be set to zero; if the sum is greater, only the first size locations will be stored.

| Note

- If p4 is positive, functions are post-normalized (rescaled to a maximum absolute value of 1 after generation). A negative p4 will cause rescaling to be skipped.

- Discrete-point linear interpolation implies an increase or decrease along a segment by equal differences between adjacent locations; exponential interpolation implies that the progression is by equal ratio. In both forms the interpolation from a to b is such as to assume that the value b will be attained in the n + 1th location. For discontinuous functions, and for the segment encompassing the end location, this value will not actually be reached, although it may eventually appear as a result of final scaling.

## Examples

Here is a simple example of the GEN07 routine. It uses the files gen07.orc and gen07.sco. It will create a single-cycle sawtooth whose discontinuity is mid-way in the stored function. Here is its diagram:

Diagram of the waveform generated by GEN07.

Example 1. A simple example of the GEN07 routine.

    /* gen07.orc */
    ; Initialize the global variables.
    sr = 44100
    kr = 4410
    ksmps = 10
    nchnls = 1

    ; Instrument #1.
    instr 1
      kamp = 30000
      kcps = 440
      ifn = 1

      ; Play the sine wave stored in Table #1.
      a1 oscil kamp, kcps, ifn
      out a1
    endin
    /* gen07.orc */

    /* gen07.sco */
    ; Table #1: a sawtooth wave (using GEN07).
    f 1 0 256 7 0 128 1 0 -1 128 0

    ; Play Instrument #1 for 2 seconds.
    i 1 0 2
    e
    /* gen07.sco */

## See Also

GEN05, GEN06, and GEN08

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