Programmer Guide/SPU Reference/LOG - Revision history

193.171.195.48 at 11:39, 2 May 2011

2011-05-02T11:39:36Z

← Older revision		Revision as of 13:39, 2 May 2011
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	note:		note:
	:The logarithm is computed using the following formula: <code>y = ln(a)/ln(b)<code>.		:The logarithm is computed using the following formula: <code>y = ln(a)/ln(b)</code>.
	:<code>ln</code> is the natural logarithm and both <code>a</code> and <code>b</code> must be greater than zero		:<code>ln</code> is the natural logarithm and both <code>a</code> and <code>b</code> must be greater than zero
	;See also:		;See also:
	<[[../#Signal Processing Atoms\|SP-atoms]]>		<[[../#Signal Processing Atoms\|SP-atoms]]>
	<!-- AN, 2.5.2011 -->		<!-- AN, 2.5.2011 -->

193.171.195.48 at 11:39, 2 May 2011

2011-05-02T11:39:26Z

← Older revision		Revision as of 13:39, 2 May 2011
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	\|}		\|}
	with: 0 ≤ i < length of <var>A<sub>vector</sub></var>		with: 0 ≤ i < length of <var>A<sub>vector</sub></var>

			note:
			:The logarithm is computed using the following formula: <code>y = ln(a)/ln(b)<code>.
			:<code>ln</code> is the natural logarithm and both <code>a</code> and <code>b</code> must be greater than zero
	;See also:		;See also:
	<[[../#Signal Processing Atoms\|SP-atoms]]>		<[[../#Signal Processing Atoms\|SP-atoms]]>
	<!-- AN, 2.5.2011 -->		<!-- AN, 2.5.2011 -->

193.171.195.48 at 11:36, 2 May 2011

2011-05-02T11:36:59Z

← Older revision		Revision as of 13:36, 2 May 2011
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	\|<var>A<sub>vector</sub></var>, <var>B<sub>number</sub></var>		\|<var>A<sub>vector</sub></var>, <var>B<sub>number</sub></var>
	\|<var>Y<sub>vector</sub></var>		\|<var>Y<sub>vector</sub></var>
	\|<var>Y</var>[i] = <var>A</var>~~[i] ^~~ <var>B</var>		\|<var>Y</var>[i] = log<sub><var>B</var></sub>(<var>A</var>[i])
	\|-		\|-
	\|<var>A<sub>vector</sub></var>, <var>B<sub>vector</sub></var>		\|<var>A<sub>vector</sub></var>, <var>B<sub>vector</sub></var>
	\|<var>Y<sub>vector</sub></var>		\|<var>Y<sub>vector</sub></var>
	\|<var>Y</var>[i] = <var>A</var>[i] ^ <var>B</var>[i]		\|<var>Y</var>[i] = log<sub><var>B</var>[i]</sub>(<var>A</var>[i])
	\|}		\|}
	with: 0 ≤ i < length of <var>A<sub>vector</sub></var>		with: 0 ≤ i < length of <var>A<sub>vector</sub></var>

193.171.195.48 at 11:36, 2 May 2011

2011-05-02T11:36:19Z

← Older revision		Revision as of 13:36, 2 May 2011
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	{{DISPLAYTITLE:{{SUBPAGENAME}}}}		{{DISPLAYTITLE:{{SUBPAGENAME}}}}
	~~====LOG====~~		Compute logarithm of <var>A</var> to the base <var>B</var>.
			==<code>[SPU LOG <var>A B</var> OUT <var>Y</var>]</code>==
	==~~===Usage:=====~~		{\|class="einrahmen"
			!In !!Out !!Description
	<code>LOG <var>~~a b~~</var></code>

	===~~==Inputs:=====~~

	{\|
	\|-		\|-
	\|a		\|<var>A<sub>number</sub></var>, <var>B<sub>number</sub></var>
	\|number ~~or vector~~		\|<var>Y<sub>number</sub></var>
			\|<var>Y</var> = log<sub><var>B</var></sub>(<var>A</var>)
	\|-		\|-
	\|b		\|<var>A<sub>vector</sub></var>, <var>B<sub>number</sub></var>
	\|~~number or~~ vector		\|<var>Y<sub>vector</sub></var>
	\|}		\|<var>Y</var>[i] = <var>A</var>[i] ^ <var>B</var>

	=~~====Outputs:=====~~

	{\|
	\|-		\|-
	\|<var>y</var>		\|<var>A<sub>vector</sub></var>, <var>B<sub>vector</sub></var>
	\|~~number or~~ vector ~~(same type as a)~~		\|<var>Y<sub>vector</sub></var>
			\|<var>Y</var>[i] = <var>A</var>[i] ^ <var>B</var>[i]
	\|}		\|}
			with: 0 ≤ i < length of <var>A<sub>vector</sub></var>
	~~=====Function~~:~~=====~~		;See also:
			<[[../#Signal Processing Atoms\|SP-atoms]]>
	~~Compute logarithm~~ of <var>~~a</var> to base~~ <~~var~~>~~b</var>.~~		<!-- AN, 2.5.2011 -->

	~~if <var>a</var> and <var>b</var> are numbers: <var>y</var> = log<var>b~~</~~var>(<var~~>a</var>)

	~~if <var>a</var> is a vector and <var>b</var> a number~~: ~~<var>y</var>[i] = log<var>b</var>(<var>a</var>[i])~~

	~~if <var>a~~<~~/var> and <var>b</var> are vectors: <var>y</var>[i] = log<var>b</var>~~[~~i](<var>a</var>~~[~~i])~~

	~~Both <var>a<~~/~~var>~~\|~~<var>a</var>[i~~] ~~and <var>b</var>\|<var>b</var>[i~~] ~~must be greater than zero (otherwise the result is set to 0). If <var~~>~~a</var>\|~~<~~var>a</var>[i] is smaller than the smallest number representable in single precision~~, ~~the logarithm is set to the exponent of this number~~.

Admin: 1 revision: Initial import

2010-11-18T16:31:54Z

1 revision: Initial import

← Older revision	Revision as of 18:31, 18 November 2010
(No difference)

193.171.195.8: initial import

2010-05-17T13:05:27Z

initial import

New page

{{DISPLAYTITLE:{{SUBPAGENAME}}}}
====LOG====

=====Usage:=====

<code>LOG <var>a b</var></code>

=====Inputs:=====

{|
|-
|a
|number or vector
|-
|b
|number or vector
|}

=====Outputs:=====

{|
|-
|<var>y</var>
|number or vector (same type as a)
|}

=====Function:=====

Compute logarithm of <var>a</var> to base <var>b</var>.

if <var>a</var> and <var>b</var> are numbers: <var>y</var> = log<var>b</var>(<var>a</var>)

if <var>a</var> is a vector and <var>b</var> a number: <var>y</var>[i] = log<var>b</var>(<var>a</var>[i])

if <var>a</var> and <var>b</var> are vectors: <var>y</var>[i] = log<var>b</var>[i](<var>a</var>[i])

Both <var>a</var>|<var>a</var>[i] and <var>b</var>|<var>b</var>[i] must be greater than zero (otherwise the result is set to 0). If <var>a</var>|<var>a</var>[i] is smaller than the smallest number representable in single precision, the logarithm is set to the exponent of this number.