# Math.im

##### S3 Group Generic methods for images

These are group generic methods for images of class `"im"`

, which
allows for usual mathematical functions and operators to be applied
directly to images. See Details for a list of implemented functions.

##### Usage

```
## S3 methods for group generics have prototypes:
````Math(x, \dots)`

`Ops(e1, e2)`

`Complex(z)`

`Summary(\dots, na.rm=FALSE, drop=TRUE)`

##### Arguments

- x, z, e1, e2
objects of class

`"im"`

.- …
further arguments passed to methods.

- na.rm,drop
Logical values specifying whether missing values should be removed. This will happen if either

`na.rm=TRUE`

or`drop=TRUE`

. See Details.

##### Details

Below is a list of mathematical functions and operators which are
defined for images. Not all functions will make sense for all
types of images. For example, none of the functions in the `"Math"`

group
make sense for character-valued images. Note that the `"Ops"`

group methods are implemented using `eval.im`

, which tries
to harmonise images via `harmonise.im`

if they aren't
compatible to begin with.

Group

`"Math"`

:`abs`

,`sign`

,`sqrt`

,`floor`

,`ceiling`

,`trunc`

,`round`

,`signif`

`exp`

,`log`

,`expm1`

,`log1p`

,`cos`

,`sin`

,`tan`

,`cospi`

,`sinpi`

,`tanpi`

,`acos`

,`asin`

,`atan`

`cosh`

,`sinh`

,`tanh`

,`acosh`

,`asinh`

,`atanh`

`lgamma`

,`gamma`

,`digamma`

,`trigamma`

`cumsum`

,`cumprod`

,`cummax`

,`cummin`

Group

`"Ops"`

:`"+"`

,`"-"`

,`"*"`

,`"/"`

,`"^"`

,`"%%"`

,`"%/%"`

`"&"`

,`"|"`

,`"!"`

`"=="`

,`"!="`

,`"<"`

,`"<="`

,`">="`

,`">"`

Group

`"Summary"`

:`all`

,`any`

`sum`

,`prod`

`min`

,`max`

`range`

Group

`"Complex"`

:`Arg`

,`Conj`

,`Im`

,`Mod`

,`Re`

For the `Summary`

group, the generic has an argument
`na.rm=FALSE`

, but for pixel images it makes
sense to set `na.rm=TRUE`

so that pixels outside the domain of
the image are ignored. To enable this, we added the argument
`drop`

. Pixel values that are `NA`

are removed
if `drop=TRUE`

or if `na.rm=TRUE`

.

##### See Also

`eval.im`

for evaluating expressions involving images.

##### Examples

```
# NOT RUN {
## Convert gradient values to angle of inclination:
V <- atan(bei.extra$grad) * 180/pi
## Make logical image which is TRUE when heat equals 'Moderate':
A <- (gorillas.extra$heat == "Moderate")
## Summary:
any(A)
## Complex:
Z <- exp(1 + V * 1i)
Z
Re(Z)
# }
```

*Documentation reproduced from package spatstat, version 1.63-0, License: GPL (>= 2)*