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*

Multiplication operator.

Arithmetic operators perform operations of change-sign (negate), don't-change-sign, logical AND logical OR, add, subtract, multiply and divide. Note that a value or an expression may fall between two of these operators, either of which could take it as its left or right argument, as in

\[ a + b * c. \]

In such cases three rules apply:

  1. \(*\) and \(/\) bind to their neighbors more strongly than \(+\) and \(-\). Thus the above expression is taken as:
    \(a + (b * c)\) with \(*\) taking \(b\) and \(c\) and then \(+\) taking \(a\) and \(b * c\).

  2. \(+\) and \(-\) bind more strongly than &&, which in turn is stronger than ||:
    \(a \;\&\&\; b - c \;||\; d\) is taken as \((a \;\&\&\; (b - c))\;||\; d\)

  3. When both operators bind equally strongly, the operations are done left to right:
    \(a - b - c\) is taken as \((a - b) - c\)

Parentheses may be used as above to force particular groupings.

Syntax

a * b  (no rate restriction)

where the arguments \(a\) and \(b\) may be further expressions.

Arguments

The arguments of * can be scalar values or k-rate one dimensional arrays (vectors), or any combination. If one of the arguments is an array, so is the value.

Examples

Here is an example of the * operator. It uses the file multiplies.csd.

Example of the * operator.
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<CsoundSynthesizer>
<CsOptions>
; Select audio/midi flags here according to platform
-odac     ;;;realtime audio out
;-iadc    ;;;uncomment -iadc if realtime audio input is needed too
; For Non-realtime ouput leave only the line below:
; -o multiplies.wav -W ;;; for file output any platform
</CsOptions>
<CsInstruments>

sr = 44100
ksmps = 32
nchnls = 2
0dbfs  = 1

instr 1

kenv    expon 0.01, p3, 1
aout    poscil  0.8*kenv, 440, 1        ;multiply amplitude from 0 to 1 * 0.8
printks "base amplitude * rising expon output = 0.8 * %f\n", .1, kenv
        outs    aout, aout
endin

</CsInstruments>
<CsScore>

f 1 0 16384 10 1        ; sine wave

i 1 0 2

e

</CsScore>
</CsoundSynthesizer>

Its output should include a line like this:

base amplitude * rising expon output = 0.8 * 0.010000
base amplitude * rising expon output = 0.8 * 0.012589
..........
base amplitude * rising expon output = 0.8 * 0.794328
base amplitude * rising expon output = 0.8 * 0.998466

See also

Arithmetic and Logic Operations

Credits

Arithmetic on vectors is new in version 6.00