Difference between revisions of "Math functions"

m (Added see also to Sigmoid, Logit, ProductLog)
 
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[[Category:Analytica User Guide]]
 
[[Category:Analytica User Guide]]
 
[[Category: Math Functions]]
 
[[Category: Math Functions]]
<breadcrumbs>Analytica User Guide > Using Expressions > {{PAGENAME}}</breadcrumbs>
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<breadcrumbs>Analytica User Guide > Expressions > {{PAGENAME}}</breadcrumbs>
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{{ReleaseBar}}
  
 
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These functions can be accessed from the '''Math '''library from the [[Definition menu]].
These functions can be accessed from the '''Math '''library from the '''Definition '''menu.
 
  
 
'''Abs(x)''': Returns the absolute value of «x». When «x» is complex, returns the magnitude, see [[Complex number functions]]. See also [[Abs]]().
 
'''Abs(x)''': Returns the absolute value of «x». When «x» is complex, returns the magnitude, see [[Complex number functions]]. See also [[Abs]]().
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:<code>Ceil(Pi, 4) &rarr; 3.1416</code>
 
:<code>Ceil(Pi, 4) &rarr; 3.1416</code>
 
:<code>Ceil(-12345, -2) &rarr; -12300</code>
 
:<code>Ceil(-12345, -2) &rarr; -12300</code>
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'''Ceil(x, ,dateUnit)''': Rounds a date-time «x» up to the indicated «dateUnit», where «dateUnit» can be 'Y', 'Q', 'M', 'D', 'h', 'm', or 's' (year, quarter, month, day, hour, minute, second).
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:<code>Ceil(26-July-2017, dateUnit:'Y') &rarr; 1-Jan-2018</code>
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:<code>Ceil(26-July-2017, dateUnit:'M') &rarr; 1-Aug-2017</code>
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:<code>Ceil(26-July-2017, dateUnit:'D') &rarr; 26-July-2017</code>
  
 
'''Floor(x)''': Returns the largest integer that is smaller than or equal to «x». See also [[Floor]]().
 
'''Floor(x)''': Returns the largest integer that is smaller than or equal to «x». See also [[Floor]]().
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:<code>Floor(Pi, 4) &rarr; 3.1415</code>
 
:<code>Floor(Pi, 4) &rarr; 3.1415</code>
 
:<code>Floor(-12345, -2) &rarr; -12400</code>
 
:<code>Floor(-12345, -2) &rarr; -12400</code>
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'''Floor(x, ,dateUnit)''': Rounds a date-time «x» down to the indicated «dateUnit», where «dateUnit» can be 'Y', 'Q', 'M', 'D', 'h', 'm', or 's' (year, quarter, month, day, hour, minute, second).
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:<code>Floor(26-July-2017, dateUnit:'Y') &rarr; 1-Jan-2017</code>
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:<code>Floor(26-July-2017, dateUnit:'M') &rarr; 1-July-2017</code>
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:<code>Floor(26-July-2017, dateUnit:'D') &rarr; 26-July-2017</code>
  
 
'''Round(x)''': Returns the value of «x» rounded to the nearest integer. See also [[Round]]().
 
'''Round(x)''': Returns the value of «x» rounded to the nearest integer. See also [[Round]]().
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:<code>Exp(-4) &rarr; 0.01832</code>
 
:<code>Exp(-4) &rarr; 0.01832</code>
  
'''Ln(x)''': Returns the natural logarithm of «x», which must be positive unless the system variable '''Enable-ComplexNumbers''' is set. See also [[Ln]]().
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'''Ln(x)''': Returns the natural logarithm of «x», which must be positive unless the system variable [[EnableComplexNumbers]] is set. See also [[Ln]]().
 
:<code>Ln(150) &rarr; 5.011</code>
 
:<code>Ln(150) &rarr; 5.011</code>
 
:<code>Ln(Exp(5)) &rarr; 5</code>
 
:<code>Ln(Exp(5)) &rarr; 5</code>
  
'''Logten(x)''': Returns the logarithm to the base 10 of «x», which must be positive unless the system variable '''EnableComplexNumbers''' is set. See also [[Logten]]().
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'''Logten(x)''': Returns the logarithm to the base 10 of «x», which must be positive unless the system variable [[EnableComplexNumbers]] is set. See also [[Logten]]().
 
:<code>Logten(180) &rarr; 2.255</code>
 
:<code>Logten(180) &rarr; 2.255</code>
 
:<code>Logten(10^30) &rarr; 30</code>
 
:<code>Logten(10^30) &rarr; 30</code>
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:<code>Sqr(-4) &rarr; 16</code>
 
:<code>Sqr(-4) &rarr; 16</code>
  
'''Sqrt(x)''': Returns the square root of «x». «x» must be positive unless the system variable '''EnableComplex-Numbers''' is set. See also [[Sqrt]]().
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'''Sqrt(x)''': Returns the square root of «x». «x» must be positive unless the system variable [[EnableComplexNumbers]] is set. See also [[Sqrt]]().
 
:<code>Sqrt(25) &rarr; 5 </code>
 
:<code>Sqrt(25) &rarr; 5 </code>
 
:<code>Sqrt(-1) &rarr; NAN</code>
 
:<code>Sqrt(-1) &rarr; NAN</code>
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:<code>Factorial(0) &rarr; 1</code>
 
:<code>Factorial(0) &rarr; 1</code>
 
If «x» is not an integer, it rounds «x» to the nearest integer before taking the factorial.
 
If «x» is not an integer, it rounds «x» to the nearest integer before taking the factorial.
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 +
'''Logit(p)''': The inverse of the [[Sigmoid]] function, is defined for <code>0 < p < 1</code> and is equal to <code>[[Ln]](p / (1-p))</code>. See alse [[Logit]]().
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:<code>Logit(0.5) &rarr;0</code>
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:<code>Logit(0.25) &rarr; -1.099</code>
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{{Release|5.0||'''ProductLog(z)''': Returns the value for x that solves <code>z {{=}} x * [[Exp]](x)</code>. It is also known as the Lambert W function. It is real-valued for a real-valued parameter with <code>z &ge; -[[Exp]](-1)</code>. It is also defined for all complex numbers. For real-valued '''z''' with <code>z<-[[Exp]](-1)</code>, a complex result is returned only when [[EnableComplexNumbers]] is on, and in which case, the so called ''first branch'' or ''upper branch'' (<math>W_0(z)</math>) is returned. See also [[ProductLog]]().
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:<code>ProductLog(0) &rarr; 0</code>
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:<code>ProductLog(100) &rarr; 3.386</code>
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::<code> 3.386 * Exp(3.386) &rarr; 100</code>
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}}
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'''Sigmoid(x)''': The sigmoid function is also called the logistic function, the expit function, or the inverse logit function. It serves as a continuous approximation to the step function <code>(x>=0)</code>. It approaches 0 as '''x''' approaches <code>-Inf</code>, approaches 1 as x approaches <code>Inf</code> and is 1/2 at x=0. It is equal to <code>1/(1+[[Exp]](-x))</code>. See also [[Sigmoid]]().
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:<code>Sigmoid(0) &rarr; 0.5</code>
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:<code>Sigmoid(1) &rarr; 0.7311</code>
  
 
'''Cos(x), Sin(x), Tan(x)''': Return the cosine, sine, and tangent of «x», «x» assumed in degrees. See also [[Cos]](x), [[Sin]](x), [[Tan]](x).
 
'''Cos(x), Sin(x), Tan(x)''': Return the cosine, sine, and tangent of «x», «x» assumed in degrees. See also [[Cos]](x), [[Sin]](x), [[Tan]](x).
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* [[Numbers]]
 
* [[Numbers]]
 
* [[Number formats]]
 
* [[Number formats]]
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* [[Text, Date, Math, and Financial Functions]]
 
* [[Advanced math functions]]
 
* [[Advanced math functions]]
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* [[Complex number functions]]
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* [[EnableComplexNumbers]]
 
* [[Operators]]
 
* [[Operators]]
 
* [[Sum]]
 
* [[Sum]]
 
* [[Product]]
 
* [[Product]]
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<footer>Function calls and parameters / {{PAGENAME}} / Numbers and text</footer>
 
<footer>Function calls and parameters / {{PAGENAME}} / Numbers and text</footer>

Latest revision as of 17:48, 4 August 2017



Release:

4.6  •  5.0  •  5.1  •  5.2  •  5.3  •  5.4  •  6.0  •  6.1  •  6.2  •  6.3  •  6.4  •  6.5


These functions can be accessed from the Math library from the Definition menu.

Abs(x): Returns the absolute value of «x». When «x» is complex, returns the magnitude, see Complex number functions. See also Abs().

Abs(180) → 180
Abs(-210) → 210

Ceil(x): Returns the smallest integer that is greater than or equal to «x». See also Ceil().

Ceil(3.1) → 4
Ceil(5) → 5
Ceil(-2.9999) → -2
Ceil(-7) → -7

Ceil(x, digits): Returns the smallest number with the indicated of digits to the right of the decimal that is greater than or equal to «x». See also Ceil().

Ceil(Pi, 4) → 3.1416
Ceil(-12345, -2) → -12300

Ceil(x, ,dateUnit): Rounds a date-time «x» up to the indicated «dateUnit», where «dateUnit» can be 'Y', 'Q', 'M', 'D', 'h', 'm', or 's' (year, quarter, month, day, hour, minute, second).

Ceil(26-July-2017, dateUnit:'Y') → 1-Jan-2018
Ceil(26-July-2017, dateUnit:'M') → 1-Aug-2017
Ceil(26-July-2017, dateUnit:'D') → 26-July-2017

Floor(x): Returns the largest integer that is smaller than or equal to «x». See also Floor().

Floor(2.999) → 2
Floor(3) → 3
Floor(-2.01) → -3
Floor(-5) → -5

Floor(x, digits): Returns the largest number with the indicated number of digits past the decimal that is less than or equal to «x». See also Floor().

Floor(Pi, 4) → 3.1415
Floor(-12345, -2) → -12400

Floor(x, ,dateUnit): Rounds a date-time «x» down to the indicated «dateUnit», where «dateUnit» can be 'Y', 'Q', 'M', 'D', 'h', 'm', or 's' (year, quarter, month, day, hour, minute, second).

Floor(26-July-2017, dateUnit:'Y') → 1-Jan-2017
Floor(26-July-2017, dateUnit:'M') → 1-July-2017
Floor(26-July-2017, dateUnit:'D') → 26-July-2017

Round(x): Returns the value of «x» rounded to the nearest integer. See also Round().

Round(1.8) → 2
Round(-2.8) → -3
Round(1.499) → 1
Round(-2.499) → -2

Round(x, digits): Rounds the value of «x» to the number of decimal digits, indicated by «digits», to the right of the decimal point. See also Round().

Round(Pi, 1) → 3.100
Round(Pi, 3) → 3.142
Round(14243.4, -2) → 14200

Note: The Number Format setting determines how many digits are included when a number is displayed, while Round(x,digits) returns a new rounded number so that the rounded value can be used in subsequent computations.

Exp(x): Returns the exponential of «x», e raised to the power of «x». See also Exp().

Exp(5) → 148.4
Exp(-4) → 0.01832

Ln(x): Returns the natural logarithm of «x», which must be positive unless the system variable EnableComplexNumbers is set. See also Ln().

Ln(150) → 5.011
Ln(Exp(5)) → 5

Logten(x): Returns the logarithm to the base 10 of «x», which must be positive unless the system variable EnableComplexNumbers is set. See also Logten().

Logten(180) → 2.255
Logten(10^30) → 30

Sign(x): Returns -1 when «x» is negative, 1 when «x» is positive, 0 when «x» is zero, and NaN when «x» is NaN. See also Sign().

Sign(-15.2) → -1
Sign(7.3) → 1
Sign(0) → 0
Sign(0/0) → NaN

Sqr(x): Returns the square of «x». See also Sqr().

Sqr(5) → 25
Sqr(-4) → 16

Sqrt(x): Returns the square root of «x». «x» must be positive unless the system variable EnableComplexNumbers is set. See also Sqrt().

Sqrt(25) → 5
Sqrt(-1) → NAN
Sqrt(-1) → 1j { when EnableComplexNumbers is set }

Mod(x, y): Returns the remainder (modulus) of «x»/«y». See also Mod().

Mod(7, 3) → 1
Mod(12, 4) → 0
Mod(-14, 5) → -4

Factorial(x): Returns the factorial of «x», which must be between 0 and 170. See also Factorial().

Factorial(5) → 120
Factorial(0) → 1

If «x» is not an integer, it rounds «x» to the nearest integer before taking the factorial.

Logit(p): The inverse of the Sigmoid function, is defined for 0 < p < 1 and is equal to Ln(p / (1-p)). See alse Logit().

Logit(0.5) →0
Logit(0.25) → -1.099

ProductLog(z): Returns the value for x that solves z = x * Exp(x). It is also known as the Lambert W function. It is real-valued for a real-valued parameter with z ≥ -Exp(-1). It is also defined for all complex numbers. For real-valued z with z<-Exp(-1), a complex result is returned only when EnableComplexNumbers is on, and in which case, the so called first branch or upper branch ([math]\displaystyle{ W_0(z) }[/math]) is returned. See also ProductLog().

ProductLog(0) → 0
ProductLog(100) → 3.386
3.386 * Exp(3.386) → 100

Sigmoid(x): The sigmoid function is also called the logistic function, the expit function, or the inverse logit function. It serves as a continuous approximation to the step function (x>=0). It approaches 0 as x approaches -Inf, approaches 1 as x approaches Inf and is 1/2 at x=0. It is equal to 1/(1+Exp(-x)). See also Sigmoid().

Sigmoid(0) → 0.5
Sigmoid(1) → 0.7311

Cos(x), Sin(x), Tan(x): Return the cosine, sine, and tangent of «x», «x» assumed in degrees. See also Cos(x), Sin(x), Tan(x).

Cos(180) → -1
Cos(-210) → -0.866
Sin(30) → 0.5
Sin(-45) → -0.7071
Tan(45) → 1

Arctan(x): Returns the arctangent of «x» in degrees (the inverse of Tan). See also Arctan(x), Arccos(x), Arcsin(x), Arctan2(y, x) and Advanced math functions.

Arctan(0) → 0
Arctan(1) → 45
Arctan(Tan(45)) → 45

Degrees(r), Radians(d): Degrees(r) gives degrees from radians, and Radians(d) gives radians from degrees. See also Degrees(r) and Radians(d).

Degrees(Pi/2) → 90
Degrees(-Pi) → -180
Degrees(90) → -1.57079633
Degrees(180) → 3.141592654

See Also


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