Add NeuroVecSeq matrix and dense coercions

Author: bbuchsbaum

R/neurovecseq.R

@@ -248,6 +248,57 @@ setMethod(f = "linear_access",
             out
           })
 
+# Coerce NeuroVecSeq to matrix.
+setAs(from="NeuroVecSeq", to="matrix",
+      function(from) {
+        as.matrix(from)
+      })
+
+# Coerce NeuroVecSeq to DenseNeuroVec.
+setAs(from="NeuroVecSeq", to="DenseNeuroVec",
+      function(from) {
+        as.dense(from)
+      })
+
+# Coerce NeuroVecSeq to the plain in-memory NeuroVec representation.
+setAs(from="NeuroVecSeq", to="NeuroVec",
+      function(from) {
+        as.dense(from)
+      })
+
+#' Convert a NeuroVecSeq to a matrix
+#'
+#' @description
+#' Converts a \code{\linkS4class{NeuroVecSeq}} to a dense voxel-by-time matrix.
+#'
+#' @param x A NeuroVecSeq object
+#' @param ... Additional arguments
+#' @return A matrix with one row per voxel and one column per time point.
+#'
+#' @rdname as.matrix-methods
+#' @export
+setMethod(f="as.matrix", signature=signature(x="NeuroVecSeq"),
+          def=function(x, ...) {
+            mats <- lapply(x@vecs, as.matrix)
+            do.call(cbind, mats)
+          })
+
+#' Convert a NeuroVecSeq to a DenseNeuroVec
+#'
+#' @description
+#' Materializes a \code{\linkS4class{NeuroVecSeq}} as a single
+#' \code{\linkS4class{DenseNeuroVec}} with the sequence's combined space.
+#'
+#' @param x A NeuroVecSeq object
+#' @return A DenseNeuroVec containing all sequence volumes concatenated in time.
+#'
+#' @rdname as.dense-methods
+#' @export
+setMethod(f="as.dense", signature=signature(x="NeuroVecSeq"),
+          def=function(x) {
+            DenseNeuroVec(as.matrix(x), space(x))
+          })
+
 
 #' @rdname series-methods
 #' @export

man/as.dense-methods.Rd

@@ -52,6 +52,37 @@ test_that("NeuroVecSeq length equals sum of time dims", {
   expect_equal(dim(vs)[4], 10L)
 })
 
+test_that("as.matrix on NeuroVecSeq matches concatenated NeuroVec", {
+  v1 <- make_test_vec(4L)
+  v2 <- make_test_vec(6L)
+  vs <- NeuroVecSeq(v1, v2)
+  ref <- concat(v1, v2)
+
+  expect_equal(as.matrix(vs), as.matrix(ref))
+  expect_equal(as(vs, "matrix"), as.matrix(ref))
+})
+
+test_that("NeuroVecSeq can be materialized as DenseNeuroVec", {
+  v1 <- make_test_vec(4L)
+  v2 <- make_test_vec(6L)
+  vs <- NeuroVecSeq(v1, v2)
+  ref <- concat(v1, v2)
+
+  dense <- as.dense(vs)
+  coerced <- as(vs, "DenseNeuroVec")
+  plain <- as(vs, "NeuroVec")
+
+  expect_s4_class(dense, "DenseNeuroVec")
+  expect_s4_class(coerced, "DenseNeuroVec")
+  expect_s4_class(plain, "DenseNeuroVec")
+  expect_false(inherits(plain, "NeuroVecSeq"))
+  expect_equal(dim(dense), dim(ref))
+  expect_equal(space(dense), space(ref))
+  expect_equal(as.matrix(dense), as.matrix(ref))
+  expect_equal(as.matrix(coerced), as.matrix(ref))
+  expect_equal(as.matrix(plain), as.matrix(ref))
+})
+
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 # [[ extraction
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