在下面的简单示例中，投资组合在01-02的初始空头头寸为50股IBM，该头寸在01-04涵盖。吸墨纸显示实现的pnl为-4855。这是出乎意料的。看起来好像吸墨纸假设最初的50股IBM在价格0处被卖空了。关于如何使这个最小的例子工作的任何想法？如何将初始位置的成本转移到吸墨纸上？
library(blotter)
try(rm("portfolio.p",pos=.blotter), silent = TRUE)
Sys.setenv(TZ="UTC") # this is critical
currency("USD")
stock('IBM', currency="USD", multiplier=1)
getSymbols('IBM', from='2007-01-01', to='2007-01-05', src='yahoo')
initPortf('p', symbols=symbols,initPosQty=-50, initDate='2007-01-02',currency="USD")
addTxn("p", "IBM", '2007-01-04', 50, 97.1, TxnFees = 0)
updatePortf(Portfolio="p",Dates='2007-01')
.blotter$portfolio.p$symbols$IBM$posPL
# Pos.Qty Con.Mult Ccy.Mult Pos.Value Pos.Avg.Cost Txn.Value
# 2007-01-02 -50 1 1 0 0 0
# 2007-01-02 -50 0 1 0 0 0
# 2007-01-03 -50 0 1 0 0 0
# 2007-01-04 0 1 1 0 0 4855
# 2007-01-05 0 1 1 0 0 0
# Period.Realized.PL Period.Unrealized.PL Gross.Trading.PL
# 2007-01-02 0 0 0
# 2007-01-02 0 0 0
# 2007-01-03 0 0 0
# 2007-01-04 -4855 0 -4855
# 2007-01-05 0 0 0
# Txn.Fees Net.Trading.PL
# 2007-01-02 0 0
# 2007-01-02 0 0
# 2007-01-03 0 0
# 2007-01-04 0 -4855
# 2007-01-05 0 0