小编Kar*_*ner的帖子

使用withCallingHandlers()无法捕获S4泛型函数的求值参数时生成的警告.

withCallingHandlers的正常行为示意图:

### simple function that sends a warning
send_warning <- function() {
  warning('send_warning')
}
send_warning()
# Warning message:
# In send_warning() : send_warning

### the warning can be caught by withCallingHandlers
withCallingHandlers(send_warning(), warning = function(w) 
  { stop('got warning:', w) })
# Error in (function (w)  : 
#   got warning:simpleWarning in send_warning(): send_warning

现在,让我们在S4发送期间发出警告:

### simplest method ever
setGeneric('my_method', function(x) standardGeneric('my_method') )
setMethod('my_method', 'ANY', function(x) str(x) )

### call it with an argument that produces a …

我想矢量化以下操作:

V[i+1] = max(V[i] - c, V[i+1]) for i=1 to n-1 (V[0] = 0)

相应的天真伪代码是:

for (i=0; i < n; i++) {
  if (V[i]-c > V[i+1]) V[i+1] = V[i]-c
}

哪些SIMD说明有用？