=====Formula Editing Rules/Requirements=====

In many applications it is necessary to provide users with the ability to change the calculation formulas without compiling the software. We use the functionality of [[http://zone.ni.com/reference/en-XX/help/371361K-01/lvhowto/formula_node_and_express/|National Instruments LabVIEW]].

When editing formulas, you can use the following functions:\\

^Function	^Corresponding LabVIEW Function	^Description^
|abs(x)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/glang/absolute_value/|Absolute Value]]	|Returns the absolute value of x.|
|acos(x)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/glang/inverse_cosine/|Inverse Cosine]]	|Computes the inverse cosine of x in radians.|
|acosh(x)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/gmath/inverse_hyperbolic_cosine/|Inverse Hyperbolic Cosine]]	|Computes the inverse hyperbolic cosine of x.|
|asin(x)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/glang/inverse_sine/|Inverse Sine]]	|Computes the inverse sine of x in radians.|
|asinh(x)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/gmath/inverse_hyperbolic_sine/|Inverse Hyperbolic Sine]]	|Computes the inverse hyperbolic sine of x.|
|atan(x)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/glang/inverse_tangent/|Inverse Tangent]]	|Computes the inverse tangent of x in radians.|
|atan2(y,x)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/glang/inverse_tangent_2_input/|Inverse Tangent (2 Input)]]	|Computes the arctangent of y/x in radians.|
|atanh(x)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/gmath/inverse_hyperbolic_tangent/|Inverse Hyperbolic Tangent]]	|Computes the inverse hyperbolic tangent of x.|
|ceil(x)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/glang/round_to_posinfinity/|Round Toward +Infinity]]	|Rounds x to the next higher integer (smallest integer  x).|
|cos(x)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/glang/cosine/|Cosine]]	|Computes the cosine of x, where x is in radians.|
|cosh(x)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/gmath/hyperbolic_cosine/|Hyperbolic Cosine]]	|Computes the hyperbolic cosine of x.|
|cot(x)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/glang/cotangent/|Cotangent]]	|Computes the cotangent of x (1/tan(x)), where x is in radians.|
|csc(x)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/glang/cosecant/|Cosecant]]	|Computes the cosecant of x (1/sin(x)), where x is in radians.|
|exp(x)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/glang/exponential/|Exponential]]	|Computes the value of e raised to the x power.|
|expm1(x)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/glang/exponential_arg_minus_1/|Exponential (Arg) – 1]]	|Computes one less than the value of e raised to the <code>x power ((e^x) – 1).</code>|
|floor(x)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/glang/round_to_neginfinity/|Round To –Infinity]]	|Truncates x to the next lower integer (largest integer  x).|
|getexp(x)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/glang/mantissa_and_exponent/|Mantissa & Exponent]]	|Returns the exponent of x.|
|getman(x)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/glang/mantissa_and_exponent/|Mantissa & Exponent]]	|Returns the mantissa of x.|
|int(x)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/glang/round_to_nearest/|Round To Nearest]]	|Rounds x to the nearest integer.|
|intrz(x)	|—	|Rounds x to the nearest integer between x and zero.|
|ln(x)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/glang/natural_logarithm/|Natural Logarithm]]	|Computes the natural logarithm of x (to the base of e).|
|lnp1(x)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/glang/natural_logarithm_arg_1/|Natural Logarithm (Arg +1)]]	|Computes the natural logarithm of (x + 1).|
|log(x)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/glang/logarithm_base_10/|Logarithm Base 10]]	|Computes the logarithm of x (to the base of 10).|
|log2(x)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/glang/logarithm_base_2/|Logarithm Base 2]]	|Computes the logarithm of x (to the base of 2).|
|max(x,y)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/glang/max_and_min/|Max & Min]]	|Compares x and y and returns the larger value.|
|min(x,y)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/glang/max_and_min/|Max & Min]]	|Compares x and y and returns the smaller value.|
|mod(x,y)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/glang/quotient_and_remainder/|Quotient & Remainder]]	|Computes the remainder of x/y, when the quotient is rounded toward –Infinity.|
|pow(x,y)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/glang/power_of_x/|Power of X]]	|Computes x raised to the y power.|
|rand( )	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/glang/random_number_0_1/|Random Number (0 – 1)]]	|Produces a floating-point number between 0 and 1 exclusively.|
|rem(x,y)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/glang/quotient_and_remainder/|Quotient & Remainder]]	|Computes the remainder of x/y, when the quotient is rounded to the nearest integer.|
|sec(x)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/glang/secant/|Secant]]	|Computes the secant of x, where x is in radians (1/cos(x)).|
|sign(x)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/glang/sign/|Sign]]	|Returns 1 if x is greater than 0, returns 0 if x is equal to 0, and returns –1 if x is less than 0.|
|sin(x)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/glang/sine/|Sine]]	|Computes the sine of x, where x is in radians.|
|sinc(x)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/glang/sinc/|Sinc]]	|Computes the sine of x divided by x (sin(x)/x), where x is in radians.|
|sinh(x)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/gmath/hyperbolic_sine/|Hyperbolic Sine]]	|Computes the hyperbolic sine of x.|
|sizeOfDim(ary,di)	|—	|Returns the size of the dimension di specified for the array ary.|
|sqrt(x)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/glang/square_root/|Square Root]]	|Computes the square root of x.|
|tan(x)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/glang/tangent/|Tangent]]	|Computes the tangent of x, where x is in radians.|
|tanh(x)	|[[http://zone.ni.com/reference/en-XX/help/371361K-01/gmath/hyperbolic_tangent/|Hyperbolic Tangent]]	|Computes the hyperbolic tangent of x.|
\\

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You can use multiple expressions and define internal variables (i.e., a1..a9, b1..b9, etc.).

Example:
<code>
a1 = abs(Mean) - abs(Min) + rand(1);
a2 = abs(Peak) - abs(Mean)+ rand(1);
Result =a2 - a1
</code>
\\

An example of using the formula editor:\\
{{:reporting_engine:data_analysis_with_formula_editor.png?1000|}}