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This icon allows specifying formulas of one of the following types:

operations between one GRIB/Geopoints icon and a scalar
operations between two GRIB/Geopoints icons
functions of one or two GRIB/Geopoints icons or of a GRIB/Geopoints icon and a scalar value

For more complex operations please use a related icon named Formula. The result of the operation returned by Simple Formula can be either :

GRIB data - depending on the option specified in the icon menu, the resulting GRIB data can be visualised, dropped, examined or saved as a GRIB file icon on your desktop
Geopoints data - depending on the option specified in the icon menu, the resulting Geopoints data can be visualised, dropped or saved as a Geopoints file icon on your desktop

This icon cannot be called from Macro/Python but these computations can easily be implemented in both languages. If you are unsure about the exact translation, drop the prepared Simple Formula icon inside a Metview Macro/Python editor window to automatically generate the code.

The Simple Formula Editor

The Simple Formula editor belongs to a type of editors known as family editors which allows related sets of input specifications to be grouped in the same icon editor. The main computation type can be set via the Application parameter which offers these options:

F+G - operations between two GRIB/Geopoints icons
F+x - operations between GRIB/Geopoints icon and scalar
x+F - operations between scalar and GRIB/Geopoints icon
f(F) - functions of GRIB/Geopoints icon
f(F,G) - functions of two GRIB/Geopoints icons
f(F,x) - functions of GRIB/Geopoints icon and scalar
f(x,F) - functions of scalar and GRIB/Geopoints icon

To operate with this icon first you need to select which type of operation you want to use (in Application). The available parameters will then change in the editor according to your selection.

Parameter

Specifies a single input element to a formula. It uses either a text field (to accept scalars) or an icon field (to accept a GRIB/Geopoints icon) depending on the formula required.

Parameter 1

Specifies the first input element of a formula. It uses either a text field (to accept scalars) or an icon field (to accept a GRIB/Geopoints icon) depending on the formula required.

Parameter 2

Specifies the second input element of a formula. It uses either a text field (to accept scalars) or an icon field (to accept a GRIB/Geopoints icon) depending on the formula required.

Operator

Specifies the operator to be used in the formula. The options are as follows:

Operator	Description
+	Addition
-	Subtraction
*	Multiplication
/	Division
^	Power
>	Larger Than
<	Smaller Than
>=	Larger or Equal
<=	Smaller or Equal
=	Equal
<>	Not equal
and	Conjunction
or	Disjunction

Remember that the logical operators (last 4 lines) return data which is either 1 (result is true) or 0 (result is false).

Function

Specifies the function to be applied to the input defined in Parameter or in Parameter 1 and Parameter 2. The available options depend on the mode we set in Application.

When Application is set to f(F) the available options are as follows:

Function	Description
--	negative of the input
not	negation of input : returns 0 where input values are non-zero, 1 otherwise
sgn	sign of the input : -1 where input is negative, 1 where positive, 0 where null
int	integer part of the input
abs	absolute part of the input
sqrt	square root of the input
log	natural logarithm of the input
log10	logarithm base 10 of the input
exp	exponential of the input
sin	sine of input (must be in radians)
cos	cosine of input (must be in radians)
tan	tangent of input (must be in radians)
asin	arc sine of input (must be in radians)
acos	arc cosine of input (must be in radians)
atan	arc tangent of input (must be in radians)
coslat	cosine of the latitude of the input grid points
sinlat	sine of the latitude of the input grid points
count	the number of fields within the input
mean	mean field of the input. Apply to GRIB input only
rms	root mean square field of the input. Apply to GRIB input only
stdev	standard deviation field of the input. Apply to GRIB input only
sum	sum field of the input
var	variance field of the input. Apply to GRIB input only

Note that some options apply only to GRIB icon input.

When Application is set to f(F,G) the available options are as follows:

Function	Description
max	returns the maximum of the two input elements: a GRIB/Geopoints of the maximum of the input GRIB/Geopoints at each grid point or location. Output GRIB data contain the same number of fields as the maximum is taken on a field by field basis
min	as above but returning the minimum
covar	returns a GRIB field equal to the covariance of the input fieldsets. Apply only to GRIB input
div	returns the integer result of division of `F` by `G`
merge	returns a single GRIB fieldset composed of all the fields in the input GRIB fieldsets. Apply only to GRIB input
mod	returns the result of F modulo `G`
interpolate	returns a set of Geopoints at the locations of the Geopoints specified by G, with values calculated by interpolation at those points from the first field of fieldset `F`

When Application is set to f(F,x) or f(x,F) the available options are as follows:


max	returns the maximum of the two input elements: a GRIB/Geopoints of the maximum of the input GRIB/Geopoints at each grid point or location and the specified location. Output GRIB data contain the same number of fields as the maximum is taken on a field by field basis
min	as above but returning the minimum