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Type: Package
Title: A Collection of Tools for Building Cropping System Models
Version: 0.1.0
Description: A collection of tools for designing, implementing, testing, documenting and visualizing dynamic simulation cropping system models. Models are specified as a combination of state variables, parameters, intermediate factors and input data that define a system of ordinary differential equations. Specified models can be used to simulate dynamic processes using numerical integration algorithms.
License: GPL-3
Encoding: UTF-8
RoxygenNote: 7.3.2
Depends: R (≥ 4.2.0)
Suggests: deSolve, Rcpp, tinytest
NeedsCompilation: no
Packaged: 2026-03-30 20:32:52 UTC; palderman
Author: Phillip D Alderman [aut, cre], Pratishtha Poudel [aut]
Maintainer: Phillip D Alderman <phillip.alderman@okstate.edu>
Repository: CRAN
Date/Publication: 2026-04-03 08:20:15 UTC

Create a cropping systems model (CSM) data structure

Description

Create a cropping systems model (CSM) data structure

Usage

csm_create_data_structure(name, definition, variables)

Arguments

name

a length-one character vector name of a variable

definition

the definition of the data structure

variables

a list of the CSM variables (as defined with [csmbuilder::csm_create_variable()]) that are contained within the data structure

Value

a list of 'csm_data_structure' objects

Examples


# Create variables:
wth_variables <- c(
  csm_create_variable("Tair",
                      "air temperature",
                      "Celsius"),
  csm_create_variable("SRAD",
                      "solar radiation",
                      "MJ/m2/d"))

# Create weather data structure:
weather <- csm_create_data_structure("weather",
                                     "weather data",
                                     wth_variables)

Create a model definition for a Cropping System Model (CSM)

Description

Create a model definition for a Cropping System Model (CSM)

Usage

csm_create_model(state, ..., name = "model")

Arguments

state

a list vector containing CSM state variables defined using csm_create_state() in the intended order

...

optional arguments of list vectors containing CSM parameters defined using csm_create_parameter() or CSM variables defined using csm_create_variable()

name

a character string containing a name for the models

Value

a list which defines all components of a model including state variables, input variables, parameters, transformed variables and data structures.

Examples


# Define state variables
lv_state <- csm_create_state(
  c("x", "y"),
  definition = c("prey", "predator"),
  units = c("rabbits per square km", "foxes per square km"),
  expression(~alpha*x-beta*x*y, ~delta*x*y-gamma*y))

# Define parameters
lv_parameters <- csm_create_parameter(
  c("alpha", "beta", "gamma", "delta"),
  definition = c("maximum prey per capita growth rate",
                 "effect of predator population on prey death rate",
                 "predator per capita death rate",
                 "effect of prey population on predator growth rate"),
  units = c("rabbits per rabbit", "per fox",
            "foxes per fox", "foxes per rabbit"))

# Define model
lotka_volterra_model <-
  csm_create_model(
    state = lv_state,
    parms = lv_parameters)

Create a cropping systems model (CSM) parameter variable

Description

Create a cropping systems model (CSM) parameter variable

Usage

csm_create_parameter(
  name,
  definition,
  units,
  lower_bound = NULL,
  upper_bound = NULL
)

Arguments

name

a length-one character vector name of a variable

definition

a length-one character vector that defines the CSM variable

units

a length-one character vector of the units of the CSM variable

lower_bound

a numerical value providing the lower bound for the parameter

upper_bound

a numerical value providing the upper bound for the parameter

Value

a list of csm_parameter objects

Examples

# Define Lotka-Voterra parameters with single call

lv_parameters <- csm_create_parameter(
  name = c("alpha", "beta", "gamma", "delta"),
  definition = c("maximum prey per capita growth rate",
                 "effect of predator population on prey death rate",
                 "predator per capita death rate",
                 "effect of prey population on predator growth rate"),
  units = c("rabbits per rabbit", "per fox",
            "foxes per fox", "foxes per rabbit"))

# Define Lotka-Volterra parameters with multiple calls

lv_parameters <-
  c(
    csm_create_parameter(
      name = "alpha",
      definition = "maximum prey per capita growth rate",
      units = "rabbits per rabbit"),
    csm_create_parameter(
      name = "beta",
      definition = "effect of predator population on prey death rate",
      units = "per fox"),
    csm_create_parameter(
      name = "gamma",
      definition = "predator per capita death rate",
      units = "foxes per fox"),
    csm_create_parameter(
      name = "delta",
      definition = "effect of prey population on predator growth rate",
      units = "foxes per rabbit"))

Create a cropping systems model (CSM) state variable

Description

Create a cropping systems model (CSM) state variable

Usage

csm_create_state(name, definition, units, equation)

Arguments

name

a length-one character vector name of a variable

definition

a length-one character vector that defines the CSM variable

units

a length-one character vector of the units of the CSM variable

equation

an R expression with the equation for the rate of change of the CSM state variable

Value

a list of csm_state objects

Examples


# Define state variables with single call

lv_state <- csm_create_state(
  c("x", "y"),
  definition = c("prey", "predator"),
  units = c("rabbits per square km", "foxes per square km"),
  expression(~alpha*x-beta*x*y, ~delta*x*y-gamma*y))

# Define state variables with multiple calls

lv_state <-
c(
  csm_create_state(
    name = "x",
    definition = "prey",
    units = "rabbits per square km",
    equation = ~alpha*x-beta*x*y),
  csm_create_state(
    name = "y",
    definition = "predator",
    units = "foxes per square km",
    equation = ~delta*x*y-gamma*y)
  )

Create a cropping systems model (CSM) transformed variable

Description

Create a cropping systems model (CSM) transformed variable

Usage

csm_create_transform(name, definition, units, equation)

Arguments

name

a length-one character vector name of a variable

definition

a length-one character vector that defines the CSM variable

units

a length-one character vector of the units of the CSM variable

equation

an R expression with the equation for the value of the transformed CSM state variable

Value

a list of csm_transform objects

Examples


# Define intermediate factor

sp_factors <- csmbuilder::csm_create_transform(
  name = "fv",
  definition = "vernalization factor",
  units = "relative progress towards complete vernalization (0-1)",
  equation = ~min(c(cum_vrn/vreq, 1)))

Create a cropping systems model (CSM) variable

Description

Create a cropping systems model (CSM) variable

Usage

csm_create_variable(name, definition, units)

Arguments

name

a length-one character vector name of a variable

definition

a length-one character vector that defines the CSM variable

units

a length-one character vector of the units of the CSM variable

Value

a list of csm_variable objects

Examples


Tair <- csm_create_variable(name = "Tair",
                            definition = "air temperature",
                            units = "Celsius")

Linearly interpolate a time-varying variable at specific time point

Description

Linearly interpolate a time-varying variable at specific time point

Usage

csm_get_at_t(
  x,
  t_ind,
  t,
  method = "linear",
  search = c("interpolation", "bisection", "bruteforce", "i=t+1")
)

Arguments

x

a vector of a time-varying values for which to interpolate

t_ind

a vector of times corresponding to the values in x

t

a single time point at which to return a value

method

a string indicating what method to use for interpolation. One of: "linear"

search

a string indicating what method to use for finding the correct indices within t_ind. One of: "bisection", "interpolation"

Value

the numeric value of the time-varying variable interpolated at time t

Modified Arrhenius function

Description

Modified Arrhenius function

Usage

csm_mod_arr(Tt, ko, H, E, To)

Arguments

Tt

temperature in Celsius

ko

reaction rate at the optimum temperature (To)

H

deactivation energy parameter

E

activation energy parameter

To

optimum temperature in Celsius

Value

a numeric value of the reaction rate at temperature Tt

Render a defined Cropping System Model (CSM)

Description

Render a defined Cropping System Model (CSM)

Usage

csm_render_model(
  model,
  name = "dy_dt",
  output_type = c("function", "code"),
  language = c("R", "Rcpp"),
  arg_alias = NULL,
  insert_functions = NULL
)

Arguments

model

a list vector containing a CSM as created by csm_create_model()

name

name of the resulting function

output_type

a character value indicating the type of output to produce; one of: "function" (a callable function) or "code" (computer code for the model)

language

a character value indicating which programming language into which to render the model

arg_alias

an optional named character vector whose names indicate variables for which to use an alias within the generated function and whose elements provide the corresponding alias

insert_functions

an optional list of functions to add to rendered code

Value

Either an R function object (if output_type="function") or a character vector of model code (if output_type="code") in the programming language specified by language.

Examples


# Define state variables
lv_state <- csm_create_state(
  c("x", "y"),
  definition = c("prey", "predator"),
  units = c("rabbits per square km", "foxes per square km"),
  expression(~alpha*x-beta*x*y, ~delta*x*y-gamma*y))

# Define parameters
lv_parameters <- csm_create_parameter(
  c("alpha", "beta", "gamma", "delta"),
  definition = c("maximum prey per capita growth rate",
                 "effect of predator population on prey death rate",
                 "predator per capita death rate",
                 "effect of prey population on predator growth rate"),
  units = c("rabbits per rabbit", "per fox",
            "foxes per fox", "foxes per rabbit"))

# Define model
lotka_volterra_model <-
  csm_create_model(
    state = lv_state,
    parms = lv_parameters)

# Render model into raw R code
lotka_volterra_code <-
  csm_render_model(lotka_volterra_model,
                   output_type = "code",
                   language = "R")

# Render model into a callable R function
lotka_volterra_fun <-
  csm_render_model(lotka_volterra_model,
                   output_type = "function",
                   language = "R")

Run a Cropping System Model (CSM) simulation

Description

Run a Cropping System Model (CSM) simulation

Usage

csm_run_sim(model_function, y_init, t, ..., method = "euler")

Arguments

model_function

a rendered model produced by csm_render_model()

y_init

a vector of initial values for the model state variables

t

an optional vector of time points for which simulated model outputs are desired

...

additional arguments to pass to model_function for simulation

method

numerical integration method to be used. See deSolve::ode() for more details

Value

a data frame with one row for each time point specified by t

Examples


# Define state variables
lv_state <- csm_create_state(
  c("x", "y"),
  definition = c("prey", "predator"),
  units = c("rabbits per square km", "foxes per square km"),
  expression(~alpha*x-beta*x*y, ~delta*x*y-gamma*y))

# Define parameters
lv_parameters <- csm_create_parameter(
  c("alpha", "beta", "gamma", "delta"),
  definition = c("maximum prey per capita growth rate",
                 "effect of predator population on prey death rate",
                 "predator per capita death rate",
                 "effect of prey population on predator growth rate"),
  units = c("rabbits per rabbit", "per fox",
            "foxes per fox", "foxes per rabbit"))

# Define model
lotka_volterra_model <-
  csm_create_model(
    state = lv_state,
    parms = lv_parameters)

# Render model into a callable R function
lotka_volterra_fun <-
  csm_render_model(lotka_volterra_model,
                   output_type = "function",
                   language = "R")

# Run model simulation
lotka_volterra_out <-
  csm_run_sim(model_function = lotka_volterra_fun,
              y_init = c(x = 10,
                         y = 10),
              t = csm_time_vector(0, 100, 0.01),
              parms = c(alpha = 1.1,
                        beta = 0.4,
                        gamma = 0.1,
                        delta = 0.4))

Generate vector of times for simulation

Description

Generate vector of times for simulation

Usage

csm_time_vector(t_init, t_max, dt = 1)

Arguments

t_init

a numerical value providing the initial time to use for simulation

t_max

a numerical value providing the final time to use for simulation

dt

a numerical value providing the size of the time step to use for simulation

Value

a numeric vector

Examples


csm_time_vector(0, 100, dt = 0.01)

Determine if object is a data structure

Description

Determine if object is a data structure

Usage

is_data_structure(x)

Arguments

x

any R object

Value

a logical value indicating whether or not x is of class csm_data_structure

Determine if object is a model input

Description

Determine if object is a model input

Usage

is_input(x)

Arguments

x

any R object

Value

a logical value indicating whether or not x is an input variable

Determine if object is a model parameter

Description

Determine if object is a model parameter

Usage

is_parameter(x)

Arguments

x

any R object

Value

a logical value indicating whether or not x is of class csm_parameter

Determine if object is state variable

Description

Determine if object is state variable

Usage

is_state_variable(x)

Arguments

x

any R object

Value

a logical value indicating whether or not x is of class csm_state

Determine if object is a transformed variable

Description

Determine if object is a transformed variable

Usage

is_transform(x)

Arguments

x

any R object

Value

a logical value indicating whether or not x is of class csm_transform

These binaries (installable software) and packages are in development.
They may not be fully stable and should be used with caution. We make no claims about them.
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