spray (version 1.0-6)

spray-package: Sparse arrays and multivariate polynomials

Description

Functionality for sparse arrays, with emphasis on sparse arrays interpreted as multivariate polynomials.

Details

Sparse arrays are a dictionary with keys being (unsigned) integer vectors, and values floats.

See Also

multipol

Examples

# NOT RUN {

# define a spray using a matrix of indices and a vector of values:
M <- matrix(sample(0:3,21,replace=TRUE),ncol=3)
a <- spray(M,sample(7))

# there are many pre-defined simple sprays:
b <- homog(3,4)

# arithmetic operators work:
a + 2*b
a - a*b^2/4
a+b

#  we can sum over particular dimensions:
asum(a+b,1)

# differentiation is supported:
deriv(a^6,2)

# extraction and replacement work as expected:

b[1,2,1]
b[1,2,1,drop=TRUE]

b[diag(3)] <- 3



# }

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