Fix exp/log maps

R/spd-expmap.R

@@ -17,7 +17,7 @@ spd.expmap <- function(x, p){
     }
 
     p.sqrt <- sqrtm(p)
-    p.inv.sqrt <- solve(p.inv)
+    p.inv.sqrt <- solve(p.sqrt)
     return(p.sqrt %*% expm2(p.inv.sqrt %*% x %*% p.inv.sqrt) %*% p.sqrt)
 
 }

R/spd-interp-functions.R

@@ -4,7 +4,7 @@ spd.interpolate.euclidean <- function(x, y, t, ...){
 }
 
 spd.interpolate.logeuclidean <- function(x, y, t, ...){
-    return(expm((1-t)*logm(x) + t*logm(y)))
+    return(expm((1-t)*logm2(x) + t*logm2(y)))
 }
 
 spd.interpolate.riemannian <- function(x, y, t, ...){

R/spd-logmap.R

@@ -16,7 +16,7 @@ spd.logmap <- function(x, p){
     }
 
     p.sqrt <- sqrtm(p)
-    p.inv.sqrt <- solve(p.inv)
+    p.inv.sqrt <- solve(p.sqrt)
     return(p.sqrt %*% logm2(p.inv.sqrt %*% x %*% p.inv.sqrt) %*% p.sqrt)
 
 }

R/spd-transport.R

+#' Parallel transport of a tangent vector
+#'
+#' Whitens an SPD matrix using the procedure advocated by Ng, et al. (2014)
+#'
+#' @param x An SPD matrix to be whitened
+#' @param p The SPD baseline whitening matrix
+#' @param unwhiten Logical. If TRUE, reverses a previously applied whitening transform.
+#' @return A symmetric, positive-definite matrix.
+
+to   <- cov(matrix(rnorm(30), ncol = 3))
+from <- cov(matrix(rnorm(30), ncol = 3))
+x    <- cov(matrix(rnorm(30), ncol = 3))
+x    <- spd.logmap(x, from)
+
+spd.transport <- function(x, to, from){
+
+    if (!'s.mat' %in% input.type(x)){
+        stop('x must be a positive definite matrix')
+    }
+    if (!'spd.mat' %in% input.type(to)){
+        stop('to must be a positive definite matrix')
+    }
+    if (!'spd.mat' %in% input.type(from)){
+        stop('from must be a positive definite matrix')
+    }
+
+    return(x)
+
+}