R+；knitr&x2B；性能分析打印错误

我正在运行以下代码，但出于某种原因，在

for

循环中使用

charts.PerformanceSummary（）

时，它尝试产生比循环次数更多的输出。而一个简单的绘图函数似乎可以很好地工作

请查看下面的.Rmd代码，然后查看编织为html后创建的后续.md文件

PLOT TEST
====

```{r}
suppressPackageStartupMessages(require(PerformanceAnalytics))
for(i in 1:5){
  charts.PerformanceSummary(xts(rnorm(i*1000,0.0001,0.0003),Sys.Date()-c((i*1000):1)))
}
```

```{r}
for(i in 1:5){
  plot(xts(cumprod(rnorm(i*1000,0.0001,0.0003)+1),Sys.Date()-c((i*1000):1)))
}
```

给出以下.md文件

PLOT TEST
====


```r
suppressPackageStartupMessages(require(PerformanceAnalytics))
for (i in 1:5) {
    charts.PerformanceSummary(xts(rnorm(i * 1000, 1e-04, 3e-04), Sys.Date() - 
   c((i * 1000):1)))
}
```

![plot of chunk unnamed-chunk-1](figure/unnamed-chunk-11.png) ![plot of chunk unnamed-chunk-1](figure/unnamed-chunk-12.png) ![plot of chunk unnamed-chunk-1](figure/unnamed-chunk-13.png) ![plot of chunk unnamed-chunk-1](figure/unnamed-chunk-14.png) ![plot of chunk unnamed-chunk-1](figure/unnamed-chunk-15.png) ![plot of chunk unnamed-chunk-1](figure/unnamed-chunk-16.png) 



```r
for (i in 1:5) {
    plot(xts(cumprod(rnorm(i * 1000, 1e-04, 3e-04) + 1), Sys.Date() - c((i * 
    1000):1)))
}
```

![plot of chunk unnamed-chunk-2](figure/unnamed-chunk-21.png) ![plot of chunk unnamed-chunk-2](figure/unnamed-chunk-22.png) ![plot of chunk unnamed-chunk-2](figure/unnamed-chunk-23.png) ![plot of chunk unnamed-chunk-2](figure/unnamed-chunk-24.png) ![plot of chunk unnamed-chunk-2](figure/unnamed-chunk-25.png) 

请注意，第一个块尝试连接到6个输出图，但第二个块中只有5个输出图，尽管它们都具有相同的

for（i in 1:5）{

代码位

以下为

sessionInfo

sessionInfo() 
## R version 3.0.0 (2013-04-03)
## Platform: x86_64-apple-darwin10.8.0 (64-bit)
## 
## locale:
## [1] en_GB.UTF-8/en_GB.UTF-8/en_GB.UTF-8/C/en_GB.UTF-8/en_GB.UTF-8
## 
## attached base packages:
## [1] stats     graphics  grDevices utils     datasets  methods   base     
## 
## other attached packages:
## [1] PerformanceAnalytics_1.1.0 xts_0.9-3                 
## [3] zoo_1.7-9                  knitr_1.2                 
## 
## loaded via a namespace (and not attached):
## [1] digest_0.6.3    evaluate_0.4.3  formatR_0.7     grid_3.0.0     
## [5] lattice_0.20-15 stringr_0.6.2   tools_3.0.0

编辑

我也只运行了一行它自己，并有一个半修复…但不是一个做多个图表在同一块

下面是.Rmd脚本和.md输出

```{r}
charts.PerformanceSummary(xts(rnorm(1000,0.0001,0.0003),Sys.Date()-c((1000):1)))
```

```{r fig.keep='last'}
charts.PerformanceSummary(xts(rnorm(1000,0.0001,0.0003),Sys.Date()-c((1000):1)))
```

```r
charts.PerformanceSummary(xts(rnorm(1000, 1e-04, 3e-04), Sys.Date() - c((1000):1)))
```

![plot of chunk unnamed-chunk-4](figure/unnamed-chunk-41.png) ![plot of chunk unnamed-chunk-4](figure/unnamed-chunk-42.png) 



```r
charts.PerformanceSummary(xts(rnorm(1000, 1e-04, 3e-04), Sys.Date() - c((1000):1)))
```

![plot of chunk unnamed-chunk-5](figure/unnamed-chunk-5.png) 

.md输出

```{r}
charts.PerformanceSummary(xts(rnorm(1000,0.0001,0.0003),Sys.Date()-c((1000):1)))
```

```{r fig.keep='last'}
charts.PerformanceSummary(xts(rnorm(1000,0.0001,0.0003),Sys.Date()-c((1000):1)))
```

```r
charts.PerformanceSummary(xts(rnorm(1000, 1e-04, 3e-04), Sys.Date() - c((1000):1)))
```

![plot of chunk unnamed-chunk-4](figure/unnamed-chunk-41.png) ![plot of chunk unnamed-chunk-4](figure/unnamed-chunk-42.png) 



```r
charts.PerformanceSummary(xts(rnorm(1000, 1e-04, 3e-04), Sys.Date() - c((1000):1)))
```

![plot of chunk unnamed-chunk-5](figure/unnamed-chunk-5.png) 

编辑2

---

正如@agstudy所指出的，knitr似乎正在生成一个不必要的空白图像……有人知道如何删除它吗？

我认为它只是在创建一张银行图片！，，，，，我也这么认为……但我宁愿它没有……关于如何消除空白图像，有什么想法吗？对于空白图像，这是一个已知的问题；请参阅